Adding low washer fluid warning to an MJ

[Anthi4078]

Hey sorry if there’s already a post about this somewhere but I can’t find it. I was recently at a junkyard and grabbed a washer bottle with a sensor out of a Cherokee. I’m wondering what all is involved in hooking the sensor up to the light in the dash. When I had it apart to do the 4wd conversion I put socket/bulb into the spot for the low wash warning in case I ever wanted to add it so I’m hoping it’s as easy as hooking the sensor into some pre existing wiring and being done with it. Thanks for the help, Andre

[87MJTIM]

I do not believe the MJ was wired for the lower washer sensor.  The idiot light space may be present (Jeep was using the same parts for MJ & XJ).  But the wiring from the bottle to the dash is MIA.

[eaglescout526]

It’s not. I plan to dive into this but I can tell you right now, adding it is a little more on the advanced side. I believe you need to find the wire on the bulk head connector engine side that goes to the sensor plug and then find the slot on the cab side and put in the wiring with the right connector and should go up to the light itself. Ok I’m gonna go look at the electrical manual. 

[eaglescout526]

 

Actually. It might be more simple than we think. If we have the plug on the engine side, verify that all the wiring lines up, it looks like we just might have to add a ground wire to the indicator itself to get the lamp to light up…..I might attempt this sooner. 

[fiatslug87]

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[Anthi4078]

Ok, I’ve been looking at wiring diagrams for my truck (87 4.0) and as far as I can tell the low wash light shares a ground with all the gauges so   If we just send 12v to pin 15 (WHT-GRN) on the B connector it should light the indicator light. 

[eaglescout526]

As long as the sensor connector has continuity on both ends then it’ll simply be a ground. If you ever look at the plug to the “info center” it’s pretty skimpy on what’s available and I wouldn’t be surprised to find it missing the ground to the low washer lamp. 

[Ωhm]

If you installed a bulb in the IC and if you can find that connector under the hood (C168), turn KEY ON and jumper the under-hood connector. Low Washer lamp should light. If not, something is missing.

 

 

[eaglescout526]

1 minute ago, Ωhm said:

If you installed a bulb in the IC and if you can find that connector under the hood (C168), turn KEY ON and jumper the under-hood connector. Low Washer lamp should light. If not, something is missing.

 

 

 

I tried this when HOrnbrod mentioned how easy it was to add this. I added the bulb, made sure the bulb wasn’t burnt, jumped the wire to get it to light and nothing. If you look the wiring harness for the MJ shows nothing going to the indicator. On the XJ, it shows it. But it looks like it’s a ground as the engine side is mostly power. I’ll try this tomorrow when I’m working on the XJ 

[Minuit]

The dash harness wiring being present seems to be HO only.

[ghetdjc320]

8 minutes ago, Minuit said:

The dash harness wiring being present seems to be HO only.

X2, it was there on my 91 just kind of tucked away in the harness. 

[Ωhm]

Are you guys talking about the wire from C100_H6 (IP side) and C204_15 as missing on RENIX, but present on HO?

 

 

 

[eaglescout526]

I think the MJ dash harness is what separates and XJ dash harness in the Renix era. Chrysler probably added everything an XJ gets to the HO MJ harness and made it simple and cheap. So Renix is probably simple as adding the ground to C204_10 and 16.
 

It’s much like how the HO guys can add cruise control with the stalk and servo(maybe the vac canister too, not sure). 

[Minuit]

The MJ HO dash harness still doesn't have any provision for stuff like the immobilizer, ABS or overhead console (however, the engine harness contains a section of the harness that runs out to the outside temp sensor). I don't know what drove the decision to add certain things. I've certainly never seen an HO MJ with a low washer warning light as factory equipment.

 

You can add the cruise control with just the stalk and servo on the HO years.

[eaglescout526]

 

Two references I found from HOrnbrod saying all he had to do was add the socket for the indicator on his cluster for the low washer. 

[Minuit]

3 hours ago, eaglescout526 said:

 

Two references I found from HOrnbrod saying all he had to do was add the socket for the indicator on his cluster for the low washer. 

 

[Red Mistress]

Add Another to do list !

[eaglescout526]

Ok so here’s what I found:

 

According to the XJ wiring diagram, pins 10 and 16 are populated as seen here. What’s not is the power side, pin 15. Regardless it might be an easy add. It’s just a matter of figuring out where the sensor wire runs to in the C100 block and running a new wire from the interior side. 
 

I will still attempt this on my week off when I have the interior torn apart for insulation. 

[Anthi4078]

Ok so all we need is the wire coming from the sensor now. I found this diagram of the C100 connector on here and it looks like the wire from the connector comes through H6. So left most column and 3 pins up on the female side. Does anyone know how hard it is to pull pins from the C100 connector? As I might try to pull one out at the junkyard so that I can just clip it into mine. 

[eaglescout526]

They’re pretty easy. You need a small flat head strong enough to push the terminal out. I’ll take a pic of what the terminal looks like this evening. 

[schardein]

I added the sensor to my 91, put a bulb & bulb holder in the instrument cluster and it worked.  Later I switched to the 97-01 reservoir inside the driver fender (per Hornbrod's writeup, IIRC) and extended my harness to reach.

[eaglescout526]

Ok so luckily I got a full XJ dash harness recently and I went and thought, oh hey! I can pull the one wire from the harness to put into my MJ and holy fricken crap is this gonna be easy. So here’s pin 15 in the info center connector:

(I already started removing it before taking the pic)

 

here’s the wiring for it:

 

Here’s where it was in C100:

(red arrow pointing to the empty spot is where I found it. Could be different in other model years.) 

 

here's both connectors. I don't know what the cluster pin is as I haven’t tried to locate one on mouser but I know the female pins are packard 56 or series 56 connectors. 

[Anthi4078]

On 12/1/2022 at 9:53 PM, eaglescout526 said:

Ok so luckily I got a full XJ dash harness recently and I went and thought, oh hey! I can pull the one wire from the harness to put into my MJ and holy fricken crap is this gonna be easy. So here’s pin 15 in the info center connector:

(I already started removing it before taking the pic)

 

here’s the wiring for it:

 

Here’s where it was in C100:

(red arrow pointing to the empty spot is where I found it. Could be different in other model years.) 

 

here's both connectors. I don't know what the cluster pin is as I haven’t tried to locate one on mouser but I know the female pins are packard 56 or series 56 connectors. 

Do you have a picture of what you used to pop the pins out? I have a small flat head but I don’t think it’s thin enough to get in there

[eaglescout526]

3 minutes ago, Anthi4078 said:

Do you have a picture of what you used to pop the pins out? I have a small flat head but I don’t think it’s thin enough to get in there

Basically a really flat flat head. 
 

 

There’s the part number. I bought it off of mouser a year or so ago. It has come in handy for removing a lot of pins especially the pack cons and packard 56’s that are all over the AMC era. 

[Minuit]

Are there any markings on the cluster connector that could help identify it?