TJ Turn signal problem

Will miller

Will miller

Well-Known Member
Joined
Jun 10, 2015
Location
Archdale
I have a 99' Jeep Wrangler, the problem im having is with the turn signals. When I engage the turn signal switch to the left, both rear tail lights flash and the driver side front marker flash. When I engage the turn signal switch to the right, the passenger side front signal works and no lights in the rear. I have LED tail lights and stock front markers. I have put a new turn signal switch in, new EP26 flasher relay for LEDs, all grounds for each signal are good, and no bulbs are burned out. Anyone else have this problem before? Any ideas on what to troubleshoot next? Thanks!
 
Did you just install the LED tail lights? The schematics for the TJ are really simple (I'm looking at them on Google) and there's not a lot to go wrong. The front and rear turn signal lamps are on different stalk switch outputs, which is likely why you're seeing different behavior from the front and rear lamps.

I'm still digesting this...
 
The LED lights was already installed when I bought the jeep, so it's hard to tell if they were installed correctly. I will look over the schematics some tonight and start testing circuits tomorrow.
 
Okay, so this has been happening since you bought it. Each light assembly in the rear has wire for the reverse light, a wire for the parking light, and a wire for the stop/turn light. The ground appears to be through the mounting screws of the light assembly.

Do the reverse lights and brake lights work, and do the parking lights work? So is the only issue the turn signals? This shouldn't be the case, as at least one of the other functions is not working besides the turn signals if my hunch is correct. Unless one of the tail lights is bad.
 
How often do you leave it topless to get rained in?
 
Fabrik8 said:
Okay, so this has been happening since you bought it. Each light assembly in the rear has wire for the reverse light, a wire for the parking light, and a wire for the stop/turn light. The ground appears to be through the mounting screws of the light assembly.

Do the reverse lights and brake lights work, and do the parking lights work? So is the only issue the turn signals? This shouldn't be the case, as at least one of the other functions is not working besides the turn signals if my hunch is correct. Unless one of the tail lights is bad.
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Parking lights work but, the left turn signal indicator light (on the dash) stays on solid when not engaged. This is only when the headlight switch is pulled out. Then flashes normal when engaging the left turn signal. Brake lights work fine and there are no reverse lights in the tail light assembly (pictured).

The tail lights them self have three wires coming out of it (pictured). One is going to ground and two seems to be connected in to the factory harness. The only problem is with the turn signals.

Some other forms I have read, they have replaced the multifunction switch and has corrected there problems. I know I have replaced the switch already but, it wouldn't be the first time something was bad straight out of the box. So the multifunction switch could still be an issue.

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Will miller said:
Parking lights work but, the left turn signal indicator light (on the dash) stays on solid when not engaged. This is only when the headlight switch is pulled out. Then flashes normal when engaging the left turn signal. Brake lights work fine and there are no reverse lights in the tail light assembly (pictured).
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That's interesting. The indicator light is directly connected to the same wiring harness output (from the turn signal switch) as the front turn signal and side marker light, so something weird must be going on if the indicator light is staying lit but the front turn signal and marker light on that side are not staying on. That's especially strange because the indicator bulb (not an LED) is essentially just a resistor to ground, so it shouldn't be able to have a voltage across it in one part of the circuit and not another.

I'm actually leaning toward a wiring issue instead of a switch issue because of that. I would try replacing that multi-function switch, but only after some troubleshooting.

Are there signs of hacked up wiring or an aftermarket alarm install?
 
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Will miller said:
so far I've been lucky enough not get caught in the rain with the top off!
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I've seen some weird turn signal issues pop up because of moisture build up and condensation causing poor connection on the column connector. You can get some circuit voltage bleed there.
 
I think he said he replaced the multifunction switch already, and that didn't change anything. They usually go bad from water intrusion. After that, I'm with Ron - check the harness at the switch to see if there is corrosion/mouse piss/etc that is shorting the pins in the multifunction switch connector or in the harness.

After that, I think the wiring for the lights goes through the big plug in the firewall. Could be a similar issue there, if nothing is discovered under the hood.

Will miller said:
Parking lights work but, the left turn signal indicator light (on the dash) stays on solid when not engaged. This is only when the headlight switch is pulled out. Then flashes normal when engaging the left turn signal. Brake lights work fine and there are no reverse lights in the tail light assembly (pictured).

The tail lights them self have three wires coming out of it (pictured). One is going to ground and two seems to be connected in to the factory harness. The only problem is with the turn signals.
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Is the dash indicator lit all the time, or only when the park lights are on? It gets its power straight from the multi-function switch, so if it's on all the time, there's a short somewhere in the switch or the harness in the column/dash.
 
Fabrik8 said:
That's interesting. The indicator light is directly connected to the same wiring harness output (from the turn signal switch) as the front turn signal and side marker light, so something weird must be going on if the indicator light is staying lit but the front turn signal and marker light on that side are not staying on. I'm actually leaning toward a wiring issue instead of a switch issue because of that. I would try replacing that multi-function switch, but only after some troubleshooting.

Are there signs of hacked up wiring or an aftermarket alarm install?
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Thanks for the input! And no signs of hacked up wiring but I will look further into it.

shawn said:
I think he said he replaced the multifunction switch already, and that didn't change anything. They usually go bad from water intrusion. After that, I'm with Ron - check the harness at the switch to see if there is corrosion/mouse piss/etc that is shorting the pins in the multifunction switch connector or in the harness.

After that, I think the wiring for the lights goes through the big plug in the firewall. Could be a similar issue there, if nothing is discovered under the hood.



Is the dash indicator lit all the time, or only when the park lights are on? It gets its power straight from the multi-function switch, so if it's on all the time, there's a short somewhere in the switch or the harness in the column/dash.
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It is only on when the parking lights or headlight are on.

I will do some more investigating Tomorrow.
 
Since the dash light comes on when the park lights are on, my guess is that something is backfeeding the left indicator circuit off of the park circuit. The most-likely culprit is a direct short in the wiring for the left front side marker (the one in the fender). It just has two wires, and gets its ground alternately from one or the other, depending on whether or not the parking lights are on. Make sure it's lighting, both when the left indicator is on, and when the park lamps are on and the indicator is on. Unplug the bulb, see if anything changes, and give a good hard look at the wiring from the front indicator to the side indicator, looking for any damage that would cause the two wires to be shorting against one another.

After that, it would be the LED lights out back, so unplug the connectors at the tail lights and see if the behavior changes. Then plug them in one at a time and do the same.

Also, look around out back for a trailer wiring harness of any sort. *ESPECIALLY* one of the ones that plugs in to the chassis harness midway-through.

If none of those do anything, I'm back to mouse piss again. It would not be the first time I've had problems with indicator lights because of mouse piss in the dash. :rolleyes:
 
Just an update.

I went and exchanged the multifunction switch for a another one to eliminate that problem 100% and no luck. Looked at the connectors for the multifunction switch and that seemed to be fine. I've been super busy at work over the last week. So hopefully I will get back to troubleshooting this thing soon! I'll let y'all know what I find.

Thanks for the advice!
 
I've not read the thread, but what I did skim over seemed familiar. I had a shorted dual filliment bulb cause a similar occurrence once. If you've got any dual filliment bulbs I'd pull the covers or bulbs and see if the other filliment is lighting.

Sent from my SM-N910V using Tapatalk
 
mysterync said:
I've not read the thread, but what I did skim over seemed familiar. I had a shorted dual filliment bulb cause a similar occurrence once. If you've got any dual filliment bulbs I'd pull the covers or bulbs and see if the other filliment is lighting.

Sent from my SM-N910V using Tapatalk
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Would those be the dual filament bulbs that are replaced by the LED taillights that you didn't know about because you didn't read the thread?
 
Fabrik8 said:
Would those be the dual filament bulbs that are replaced by the LED taillights that you didn't know about because you didn't read the thread?
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He still has at least two of them up front, not counting the corner markers that are connected to both circuits.
 
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