Canadian daytime running lights questions

[91Pioneer]

UPDATE: So I spent the last few hours straight hyper-focusing on this and long story short I found a 1990 XJ repair manual PDF including wiring diagrams. It's on page heading 8W-198.

 

I was able to determine the following from the diagram, here are what the wires do (in order from top left to right then bottom left to right as you view my photo):

White = goes to high beams

Black = ground

Pink/Orange = goes to park brake switch (DRL defeat)

Light blue / black = goes to high beam indicators

Yellow = 12V ignition / run

 

Red = "Ignition Off Draw Connector" which I think is just a 12V battery / constant ??

Empty

Black = ground

Black = ground

Green = goes to low beams

 

It's still not clear to me if it's low or high beam headlights that are activated, but I think I may be able to choose (either hook up low or high beam). I feel I may be able to test wire this up... I think I can ignore the park brake switch and high beam indicator wires, ground all 3 grounds together, run one 12V constant, one 12V ignition and then tap into either low or high beams...

 

Wish me luck LOL - oh and by the way I have the extra headlight harness "upgrade" to install at the same time, I'm well aware of that needed upgrade, especially if I run the headlights 24/7 when the truck is turned on.

 

I was also able to find this text that describes the system:

Quote

The headlamps on Jeep vehicles sold in Canada, will 4UmnumtejheiL the ignition is turned ON. This pro- vides a constant Lights On condition while the vehicle is running. The lamps illuminate at less than 50 of normal intensity. When the vehicle is not moving and the ignition is ON, the system can be turned off by applying the parking brake.

[91Pioneer]

14 hours ago, gogmorgo said:

Wow. You were really digging there for a 15 year old thread.

 I dug these up somewhere during my quest to create a DRL-friendly relay harness that went nowhere. I can't make promises on wire colours because I was looking for a '91 (memory says that's not actually a '91 diagram but I don't recall which year it is) but the XJ DRL module is supposedly the same from '89 to '01 so that should still give you some hint at where everything is supposed to go..

 

Thanks for the reply. Yes it's a dinosaur thread but hey the truck hasn't changed in the last 15 years LOL. The 91 DRL is quite different due to the speed sensor input. I have just replied above this with my updated info that I obtained.

 

The 1990 XJ and 1991 MJ have different DRL part #s, FYI. So 89-01 should read 91-01.

[gogmorgo]

I went out and had a look at my '91 with manual trans, and confirmed the colours are the same as my diagram.

I'll need to draw this up better later, but for whatever reason the numbering scheme from my diagram looking into the harness side connector (latch tab up) is:

1   2   3   4   5

10 9   8   7   6

which seems to me like the wrong way to number your connector pins, but the colours match ¯\_(ツ)_/¯ 

So with your connector first/then my connector, under that silly numbering scheme with the same pin positions

1 - Yel - RUN / DK BLU, RUN

2 - blk/lt blu - high beam indicator / LT BLU/BLK high beam indicator

3 - pink/org - park brake switch / vacant

4 - blk - ground / vacant

5 - white - high beam / RED/ORG high beam circuit

6 - Red - constant hot / RED/WHT constant hot

7 - vacant / WHT/ORG VSS

8 - Black - ground / BLK/TAN ground

9 - Black - ground / vacant

10 - Green - High beam / VIO/WHT low beam circuit

 

Other than pin 10, which you say is a second connection to the high beam circuit (makes me suspicious) this is the same pinout, with our vacant pins overlapping the other's missing features. Looks like mine's triggered by the VSS, yours seems to be triggered by releasing the parking brake. Seeing as the park brake indicator comes on by connecting the indicator to ground, it looks like your module would be in series with that, and pin 4 would be an additional ground for completing that circuit.

I'll admit to not looking super hard but I still haven't found another part number for a '90- module other than 5600 4262, which is the same number through to '06 in the TJ, and I've found references to it going as far back as '87. But most are listing for '90-06 and nothing at all for '89, which I guess is consistent with them being mandated on vehicles built after Dec 1, 1989 as actually being for the '90 model year, not '89

 

I've confirmed through testing that my DRL module sends 5V to the high beam filaments.

 

I'm planning on visiting where the other MJ with auto trans is parked this weekend. If it's not still buried in snow I might try to see if it does anything different with the DRL. Although I don't know that the headlights are currently hooked up... interrupting projects and then not getting back to them for, going on five years now. Not the best time.

[91Pioneer]

FYI the 90 XJ DRL part # is 4437394 60043 which is different from my 91 MJ part #.

 

I made a mistake in my previous wire post - white is HI beams, green is LO beams, I will edit my post. (do you have a typo on your #10 wire?)

 

I did some experimenting today with the relay. I wired all 3 grounds together, ignored the park brake & high beam indicator wires. I then wired the "Ignition Off Draw" and Ignition wires together for power. I used a 12V power source and a voltmeter to see what happened. With this setup, I saw 4.8V on the hi beam wire, and 8.0V on the low beam wire.

 

I then wired the high beam, low beam and ground to a single headlight, this time powered by the truck's battery. That resulted in the headlight lighting up dimly with the high beam. I measured 0.1V going to the low beam wire and 2.5V to the high beam wire. I was too lazy to test a second headlight along with it but I do wonder if it might push the voltage up to like double? That's what I suspect will happen. 5V is what you are indicating you see so that kind of makes sense, eh?

 

There must be some kind of load detection logic in that relay. If I literally unplug the low beam wire from the headlight and measure the voltage then, it shows 7.2V on that wire but when it's connected it drops to 0.1V (no change to the high beam voltage). Not really a big deal to me, but this does tell me you should wire up both the high and low beam wires and not just ignore one of them.

 

For giggles I also disconnected the high beam wire, that resulted in 0V on both high and low beam wires.

 

The only things I'm left wondering right now is will my current config (ignoring 2 wires) will it have an impact on the high beam indicator? And, is there logic in the relay to turn off voltage to the high beams if it detects voltage going to the low beams? I ran out of time or I would have tested that second question.

 

I am not going to test it but I figure if I put 12V to the park brake wire it will probably turn off DRL (is that how it works?)

 

To pass safety I can't have the high beam indicator on at all times, it has to just come on with the high beams only. I may temporarily wire up my 89 Comanche with the DRL relay to test it out next.

 

My backup plan to this is to just wire a relay to trigger the low beams when the vehicle is on, that will let me pass safety and then I can do whatever after it passes.

 

 

[gogmorgo]

The reduced voltage at the high beams does turn off when you turn on the headlights, either high or low beam. You don’t want both filaments on at the same time. It should shut off the 5V to the high beams when you put power to the module’s low beam wire, although I don’t remember 
 

Something that has been run into when installing a relay harness in conjunction with DRL is that while the 5V isn’t typically going to be enough to pull in a relay and turn on full bright high beams, depending on the relay it may make it buzz, but more of a problem is it’s almost always enough to keep the relay held in, which leads to situations where your high beams may not turn off. It should require an up up down down left right left right b a sort of sequence to make it happen, like maybe switching the headlights off while the high beams are selected, which most people wouldn’t do. But it’s still a thing. When I was testing things for the DRL-friendly relay harness I confirmed that the collection of relays I had kicking around all stayed triggered until I dropped voltage down to under 2V.

Also, around the time I put the relay harness into my long bed I also unplugged the DRL module... although that was so long ago now I don’t really remember why.

But good news is the workaround is simple. You just snip the high beam wire coming off the module (pin 5) and connect it back up to the high beam circuit downstream of the relay. I’d also run the low beam wire (pin 10) down to the low beam circuit the same way. It’s not really necessary on a factory DRL vehicle, but if you need to find somewhere to hook it up anyhow, might as well run it alongside the high beam wire. 

Doing the high beam like this would also mean you wouldn’t need to tap into the high beam indicator circuit anywhere, but still retain the high beam indicator’s proper function. It won’t backfeed power from the load to

switch side of the high beam relay, so your indicator won’t ever see the 5V from the module. 

This simple workaround is what I was trying to avoid with my DRL-friendly relay harness, cutting into the factory wiring. And now I’m wondering if it’s possible to find male and female DRL module connectors to make a T harness like we do for trailer wiring… because I’m an idiot. 

[91Pioneer]

I just had the thought yesterday of getting a 10 pin headlight / header panel harness connector set from the junkyard and making a custom T-tap harness. The 90 is still there and I'm going to go back within the next 3-4 days.

I decided that if I can make the DRL relay work, I will do that first to pass inspection. And then after that I will worry about adding the extra headlight relay set that I already have. I don't want to overcomplicate things until after it gets the OK. There are some extra janky wiring things under the hood and at the fuse box so I don't want to go too far on any of these known issues. Like the blower fuse is melted so there is a jumper wire. I need to get the safety basics addressed first (DRL, all lights work, brakes, steering, etc.)

[gogmorgo]

I was thinking of a T at the DRL module more than at the header panel connector. The standard relay harness taps into the factory wiring essentially just by pushing spade connectors into the factory headlight sockets. The commercial relay harnesses go so far as to having a male H4 bulb connector to push into it. Having a T at the header panel 10-pin connector would eliminate needing to source new headlight sockets, but those are cheap and easy to come by, I haven’t dug too deep into new header panel connectors. There’s lots of used connectors out there but not all of them are exactly in reusable condition.  The other disadvantage to running stock header harness is the headlight wires aren’t up to the task for higher wattage bulbs. It’s less of a concern with everyone running LEDs, although some of the higher intensity LEDs still pull some heavy wattage. 

[Ωhm]

On 4/26/2023 at 10:14 PM, 91Pioneer said:

I have a 89 US Comanche, but I have imported it recently and need to get an inspection and now I need DRLs.

 

Is this the vehicle your looking to install DRL on?

[91Pioneer]

13 minutes ago, Ωhm said:

 

Is this the vehicle your looking to install DRL on?

Yes

[91Pioneer]

My "new" 89 spent its entire life in Miami and I've noticed many of the wires are very hard and brittle. I think it would be a smart idea to use the whole new headlight upgrade wires for safety reasons.

 

The turn signals aren't working I just noticed today but hazards work so that's a whole new thing to check. I also discovered there are no bolts or nuts holding the box on aside from the tank is attached so it's weighing the box down. Ah the joys of buying an old vehicle LOL I'm up for the task though.

[91Pioneer]

11 hours ago, gogmorgo said:

I was thinking of a T at the DRL module more than at the header panel connector.

I doubt you will find the DRL side of the DRL relay wiring connector. Unless it happens to fit various makes/models for something else besides DRL?

[gogmorgo]

13 hours ago, 91Pioneer said:

I doubt you will find the DRL side of the DRL relay wiring connector. Unless it happens to fit various makes/models for something else besides DRL?

Yeah it’s definitely a weird one. The four outer pins are bigger than the inner six. I don’t even know what to call it. Cursory searches didn’t even turn up the harness side of it. 

[91Pioneer]

You *might* have to disassemble/destroy a spare DRL relay and make your own version of that side of the connector.

 

FYI I tested out applying 12V directly to the headlight LO and HI and the DRL relay got "out of the way" so to speak. Voltage drops to 0 for the HI beam when I put 12V to the LO beam when it's all wired up. And sending 12V directly to the HI beam keeps 0V at the LO beam. The DRL seems to be working good and has some smart logic in it, but I didn't test the park brake and hi beam indicator wires (yet?).

 

I'm having second thoughts about just wiring up the new harness with the DRL at the same time. It's more work but then I'm only messing with the wiring once. And, considering I need to tap in after the new headlight relays this might be the better way to go. I had thoughts of just not running DRLs after the safety but at the end of the day I know that having DRLs is without a doubt the safer way to drive.

 

Do you know regarding the park brake, if I decide to tap into that wire, does the park brake send 12V to the park brake wire or just ground out? I'm thinking it just grounds out. I didn't look too closely at that part as I initially wasn't planning on wiring that wire. Now I'm thinking I'll just wire the whole thing up correctly and be done with it. I did not yet test the high beam indicator wire to see if I will need that, I suspect I will need to wire that up now.

[Ωhm]

You piqued my curiosity when you mentioned DRL using just a relay. Interested in looking at something. Needs proofing, untested.

[91Pioneer]

36 minutes ago, Ωhm said:

You piqued my curiosity when you mentioned DRL using just a relay. Interested in looking at something. Needs proofing, untested.

FYI the DRL relay I'm referring to is the OEM specific DRL relay used in the Canadian market. If you are handy with wiring it looks like it can be added. I'm not referring to a standard (generic) automotive relay for wiring the DRLs.

[Ωhm]

Okay, understood. 

[gogmorgo]

5 hours ago, 91Pioneer said:

You *might* have to disassemble/destroy a spare DRL relay and make your own version of that side of the connector.

 

Do you know regarding the park brake, if I decide to tap into that wire, does the park brake send 12V to the park brake wire or just ground out? I'm thinking it just grounds out. I didn't look too closely at that part as I initially wasn't planning on wiring that wire. Now I'm thinking I'll just wire the whole thing up correctly and be done with it. I did not yet test the high beam indicator wire to see if I will need that, I suspect I will need to wire that up now.

Shouldn’t be too difficult to find junk DRL modules to pirate for a connector, but that’s a messy way to do it.

 

I can go check the park brake wiring tomorrow. Not too sure where it taps into the circuit either. My understanding was the switch just connected to ground to turn the lightbulb on, but it might be grounding through the DRL module. I wouldn’t really think you’d need it though, other than slightly less draw with the key on I don’t know what the real advantage is to shutting off the DRL when the park brake is set. But GM vehicles from the early Oughts also shut the automatic headlights off with the park brake set so it’s definitely a thing. 
 

4 hours ago, Ωhm said:

You piqued my curiosity when you mentioned DRL using just a relay. Interested in looking at something. Needs proofing, untested.

If I were doing it on an MJ I’d use a relay switched by key hot to turn on the parking light circuits. 
My Lada with DRL added at the port uses two relays to turn on some function of the headlights (not sure if high or low but it’s dimmer than low beams) and the park/marker lights. Headlights shut off with handbrake but markers stay on.
 

I’ve also had to mess with early DRLs on some medium duty trucks that just use relays. I think it was a ‘91 International that used a pair of relays to run the high beams in series. Took me a little bit to figure that one out. 

[Ωhm]

9 hours ago, gogmorgo said:

If I were doing it on an MJ I’d use a relay switched by key hot to turn on the parking light circuits.

 

My thought was using the Fuel Pump B+ to the NC contact and running that to the Low Beams. You could also add the Parking Lamps to this. Now, anytime the Headlight SW is turn ON this would activate the Relay and everything goes back to normal. True, none of the features available with the DRL module.

 

 

9 hours ago, gogmorgo said:

used a pair of relays to run the high beams in series. Took me a little bit to figure that one out.

 

GM used that set up for running a pair of Cooling Fans. Low Speed in series (6vdc on both fans), High Speed in parallel (12vdc on both fans). 

[91Pioneer]

I was looking at the wiring diagrams again and noticed the park brake switch DRL wire leads back to a diode, which I quote is taped to harness near DRL module.. Well... that's a lie. I was at the junkyard again so I literally pulled the underhood harness from behind the battery where the DRL relay was, pulled it all the way behind the headlights, back in through the front driver side engine bay and kept going back until I found the diode. Guess what? It's close the master cylinder.

 

Man when I hyper focus on a topic, watch out LOL I don't think most people have the patience I can exhibit. In hindsight I should have kept going with the wiring and disconnected it from the fuse box but I just cut it near the fuse box because I was just so glad after all that to finally find the diode I was D-U-N done.

 

[91Pioneer]

@gogmorgo I don't know if you'll see this in time, but I'm wiring my T-tap 10-pin harness. Technically tonight I'm planning it and hopefully tomorrow starting cutting and soldering. Today I de-pinned the 2 extra 10-pin harnesses and discovered one is unusable (broken). Anywho....

 

My thoughts are this. I will make a male/female "T" wire harness that goes at the stock 10-pin harness location. The following wires will go straight through with no modification:

- grey-black left signal

- brown right signal

- dark blue park lights

- green/black fog

 

My plan for the remaining wires is as follows:

- white high beam - cut the wire, redirect this to the HI beam signal "upgraded" new headlight relay

- light green low beam - cut the wire, redirect this to the LO beam signal "upgraded" new headlight relay

- black ground - this will pass through the harness but I will also use this ground point for the DRL relay but not new headlight relay pair

- 12V battery - this will pass through as it's only used for fog lights, but I will also tap it directly to power the DRL relay, I think this is OK because when the DRL relay is drawing power for high beams at half voltage, there is no way the fog lights can be on (they can only be on when the low beams are on) so I think the power draw is totally fine here.

- use all new wires to the headlights themselves, leaving the old stock wires in the old harness just tucked out of the way (unused, unpowered)

- the DRL HI and LO beam wires will tap into the headlight wires AFTER the relays

 

Then, for the two new headlight relays I will:

- the signal/trigger wires are the white and light green from the 10-pin T-harness

- the grounds will get tied together and ran back as a new eyelet on the ground by the washer jug (mid-point driver inner fender)

- the main power for these I will run a new wire all the way back to the battery starter relay point with the existing 40A fuse that feeds both relays

 

I don't plan on hooking up the DRL headlight indicator wire unless required and likely not the park brake wire at this time. If I can test the park brake wire I will hook that up though so I can click the park brake on a notch or two to disable DRLs in the rare case I need to do so.

 

If you have any suggestions or thoughts please let me know.

[gogmorgo]

3 hours ago, 91Pioneer said:

@gogmorgo I don't know if you'll see this in time, but I'm wiring my T-tap 10-pin harness. Technically tonight I'm planning it and hopefully tomorrow starting cutting and soldering. Today I de-pinned the 2 extra 10-pin harnesses and discovered one is unusable (broken). Anywho....

 

My thoughts are this. I will make a male/female "T" wire harness that goes at the stock 10-pin harness location. The following wires will go straight through with no modification:

- grey-black left signal

- brown right signal

- dark blue park lights

- green/black fog

 

My plan for the remaining wires is as follows:

- white high beam - cut the wire, redirect this to the HI beam signal "upgraded" new headlight relay

- light green low beam - cut the wire, redirect this to the LO beam signal "upgraded" new headlight relay

- black ground - this will pass through the harness but I will also use this ground point for the DRL relay but not new headlight relay pair

- 12V battery - this will pass through as it's only used for fog lights, but I will also tap it directly to power the DRL relay, I think this is OK because when the DRL relay is drawing power for high beams at half voltage, there is no way the fog lights can be on (they can only be on when the low beams are on) so I think the power draw is totally fine here.

- use all new wires to the headlights themselves, leaving the old stock wires in the old harness just tucked out of the way (unused, unpowered)

- the DRL HI and LO beam wires will tap into the headlight wires AFTER the relays

 

Then, for the two new headlight relays I will:

- the signal/trigger wires are the white and light green from the 10-pin T-harness

- the grounds will get tied together and ran back as a new eyelet on the ground by the washer jug (mid-point driver inner fender)

- the main power for these I will run a new wire all the way back to the battery starter relay point with the existing 40A fuse that feeds both relays

 

I don't plan on hooking up the DRL headlight indicator wire unless required and likely not the park brake wire at this time. If I can test the park brake wire I will hook that up though so I can click the park brake on a notch or two to disable DRLs in the rare case I need to do so.

 

If you have any suggestions or thoughts please let me know.

I think the only purpose to the high beam indicator wire is to turn on the indicator only when high beams are selected. I’m guessing to prevent it from coming on in 5v DRL mode, via backfed power or something. I don’t think that’ll be an issue for you, it should still come on as normal. And your relays will block the back feeding. You won’t have power back feeding from load to switch side of the relay, at least.

 

I don’t really know how fogs fit into the situation. I don’t have factory fogs in either MJ. But I did install the switch and borrow the wiring to run a light bar… but tapped into a different power source than the dimmer switch so I could use it in conjunction with high beams. And that was getting pretty long ago.

[91Pioneer]

Is there a good place to tap an ignition-on wire near the LF headlight area? I think I may run the wire back to the Renix diagnostic connector, I see one of those is ignition on and I don't use that connector anyway.

[91Pioneer]

Ah crap, the cheap headlight harness has 18awg wire, stock is 16 ga. Shoot, I'm gonna DIY some of my own stuff instead of downgrading my wiring. Beware the cheap headlight harnesses that don't give specs.

[gogmorgo]

Some of the cheap stuff also misleads by putting extra thick insulation so their 20awg looks like 16. 
 

Not sure about a good key hot. Unless there’s something in the headlight 10-pin. Maybe in the fan temp switch wiring but I don’t know if I’d want to be tapping into that. I might just stick the wire in the same bundle as the relay harness where it runs over to the battery and then keep going to the relay box or something.

[91Pioneer]

23 hours ago, gogmorgo said:

Some of the cheap stuff also misleads by putting extra thick insulation so their 20awg looks like 16. 

That's exactly the problem, the 18 looks like 14.

 

I'm going to run a new wire back to the diagnostic port and tap ignition there, not a big deal since I plan on running a wire for battery power anyway.