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Turn signal troubles.

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My right turn signal is slow when the headlights are on and if the heater is on it almost doesn’t blink. The battery is new and I’ve tested the alternator and it’s good.  I’ve refreshed the grounds and changed the two front turn signal sockets.  Can anyone suggest something else I can check. 

Thanks in advance. 

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I installed the relay when I eliminated the C101 connector. 

I cleaned the C102 back when I eliminated the C101 connector but didn’t do it this time around. I will do that this weekend along with the fuse. 

Thanks and I’ll let you know. 

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  • 2 weeks later...

I managed to get a number off of itOhm I cleaned up the starter relay. It helped but the passenger side is still slow. On a positive it seems to have almost fixed my slow wipers. 

PocketsEmptied how in the world did you manage to take apart the fuse box. I took off the two screws inside lifted the tab from the engine bay side and can’t get it to come apart.  Do I have to takeoff the brake booster and try and pull it that way? 

While taking the screws out a relay I think just crumbled. I managed to get a number off of it 25523703. Do you know what it might be for? Thanks 



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There is a 1/4" bolt in the center of the C100 connector on the exterior side. You won't be able to see it, and it may be a work of engineering to put together something to get a socket & wrench in there, but once that's removed it will be free with some tugging. That clip is just holding the top and bottom connector together. It doesn't actually hold the interior/exterior pieces to one another. I removed the 3 bolts from my washer reservoir and set it on the brake master cyl. to make it easier.


You can remove the fuse panel from the C100 interior connector by prying the tabs on each of the screw housings. Shouldn't take much. And you can remove without going through the above process if you prefer.







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A couple things I'll throw out here.


Blower/TS gets power from big brown wire at ignition switch. It's too big a load for the switch and the blower has a crappy ground circuit.


As mentioned, the connector behind the driver side headlight is generally all corroded.




10-pin connector

I suggest unplugging EVERY electrical connection in the engine bay you can find, whether engine related or not, and spraying it out with a good electronics cleaner, visually inspecting the terminals making sure they haven’t retracted into the plastic holder, and then plugging it back together.

There’s a critical 10-pin connector for the front lighting system located in front of the air cleaner and behind the left headlight assembly. Don’t miss that one. Also be sure that the connectors to the ballast resistor mounted near the air cleaner housing are clean and tight.

ALL of the relays should be removed, the terminals wire-brushed until shiny, and the receptacles sprayed out with contact cleaner. Then plug them back in. I do this on every Renix Jeep I purchase or work on for someone else.Ballast Resistor

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On 1984 to 1990 MJs and XJs, the blower motor’s factory grounding point is on the driver side inner fender under the sheet metal screw. This ground is shared with windshield wipers, front windshield washers, rear windshield washers, AC clutch relay, fan control relay, fog lamps, fan motor, headlamps, front turn signals, front side markers, and park lamps.

So your blower motor has its ground point 10 feet away from where it is located!!

What we’re going to do is leave that ground intact and also ground the blower motor on the passenger side inner fender much closer to the blower motor itself. This will also benefit the other components on the factory ground circuit. Take this opportunity to refresh the factory ground as a matter of course. Remove the screw, scrape the surface to bare metal and reinstall the screw securely.

Here’s what I do to get the ground much closer to the blower motor and add another ground point to this overloaded ground circuit.

Find the blower motor connector on the passenger side. Red and Black two wire connector.

Find a location where the black wire can be made to reach the passenger side inner fender, and cut the wire. You may have to do some rerouting of the harness to achieve this.

Take both cut pieces of wire and put them together into a yellow eyelet and crimp. Fasten the eyelet to a place on the passenger side inner fender with a sheet metal screw after applying OxGard to the contact surfaces. Be sure to scrape the attaching point on the fender to bare metal first.

Your blower motor will now turn faster and last longer, and the other electrical components on the circuit will benefit from a better ground path.Blower motor factory ground Blower motor new ground

Ignition Switch burned.jpg

Ignition switch diagram.gif

Ignition Switch Location.jpg

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Well I took fuse block apart and cleaned up the connections as best I could. And got the same results. By the way it’s easier to remove the two bolts on the inside, then push the block in from the outside and tilt it up. You can see and access the outside bolt better. 

Eagle, I did clean up the connector behind the headlight. And put in the extra ground for the fan when I replaced it. Do you have a fix for the brown power wire you stated?

That relay was for the horn. New one doesn’t make it beep but it was hit and miss before. Put the old one back on and pushed on the metal part and it    worked but not with the button. 

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The fix for that brown wire is to inspect the ignition switch itself. Does your radio work? It should if your blower and wipers work. Then there's power being sent and may not be the switch, but possible. My initial thought was your switch is fine but since you're turning your blower on and that's causing the issue then it's voltage consistency issue between the two.


Did you clean the terminals within the fuse panel? I had corrosion issues keeping my T/S from working properly. The blower, wipers, and radio worked fine, but not my signals. That connector for the blower and signals was my issue.

You're getting power which is a good sign. I'm not entirely sure the cause of slow blinkers other than thinking the voltage is being interrupted somehow. Will have to see what others say.

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9 minutes ago, Jaime said:

They don’t seem to be affected

If Hazard Flasher works fine and LEFT side Turn Signal works fine, but RIGHT side Turn Signal is slow, I would suspect the TURN SIGNAL SW itself is faulty.



13 minutes ago, Jaime said:

but the volt gauge goes from about 13 to almost the next line when the fan is on

Perform that @cruiser54 tip, posted above, on "IMPROVING BLOWER MOTOR PERFORMANCE".

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Do you mean the switch at handle? I already ran an extra ground when I changed the fan. I was thinking of running another wire from that ground to the extra ground I have going from the battery to the frame per eagles Suggestion. 

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Ok, I had a similar issue, and it turned out to be a bad wire from the turn signal switch to the connector on the steering column.  My right turn signal would not blink.  I tested it all the way back to the steering column.  I had JUST put in a used tilt column, and there is a dk blue wire that is for the right turn signal.  THAT WIRE was broken.  With the tilt mechanism I could push my column all the way down, and while holding it there it would blink properly.  I first tested it at the column connector, realized it was the problem and I pulled the wheel off and got to the turn signal switch..  Got the switch mechanism loose (wires prevent removing it completely), cleaned up the contacts really good and put fresh dialectric grease on them, and spliced in a new wire for the rt turn signal. 


...Problem solved....

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