robsjeep

I did remove the left side marker bulb and still the left side will not flash for turn signalling. My headlamps are nice and bright, and their body ground point is nice and clean (I refreshed that ground over a year ago, I also refreshed the engine block ground and added a heavy duty cable from the block to body to replace the skinny factory braided flat cable, this done well over a year ago.
Still stumped

djgrayxj

Note from DJ

The first thing you need to do is update your profile.

1. Remove the 2001 Jeep unless you have two Jeeps the just add the 90 Cherokee.

2. Add 90 XJ 4.0L engine; Auto or manual Transmission.

Some people only look at your profile.


Now I May have found some information regarding your front light problem.

Go out to your 90XJ and raise the hood and then walk around the driver side or Left side.

And Look down to just forward of the water container for the windshield washers and you should see a bolt that has one or two black wires.

That is the body ground point for your whole front lighting system!

Remove the bolt and clean up everything really good again.

The reassembly add report back if it solved your front lighting system.

Another possible problem is if the perverse owner may have installed some the firs LED bulbs and they required a special flasher.

Roler

Oh you mean post#2
🙄

UKXJ

OK, 1st, let's just forget the side-marker, for the moment, so leave the bulb out.

Now, as I've already suggested a poor ground can cause a turn signal not to flash* & I've just reminded myself that the parking light that side is dim, which also suggests a bad ground. Soooh, both filaments of the same bulb have (different) symptoms of a bad ground. which points to that socket; is it clean (& the metal cap of the bulb)? Is the bulb a snug fit - or can you wiggle it? If you can, with the lights on, does it make any difference? Take a length of wire, at least 14 gauge, strip off about 1/2" insulation from one end & push wire down between the bulb & socket, take other (stripped) end to known good ground. if parking light is bright &/or turn signal flashes the problem is that ground. Now, withdraw wire from socket & hold it to a clean part of the outside of the socket, if lights still good, I'd be inclined to make that secondary ground wire permanent. If not, the problem is a poor connection between the bulb & the socket (dirt, corrosion, weak spring under the centre terminals).

* what about the hazards? I hear you ask, Well it it occurs to me that the draw from 3 other bulbs is enough to make the contacts in the flasher unit to open & close.

cruiser54

What happens if you swap the flashers with each other?

robsjeep

OK. As suggested my personal profile is updated.

For the bulbs, all three on left side removed (two front, one rear) , cleaned, in nice shape done a few days ago. and the main light ground near aircleaner recleaned, and the multi pin plug near right headlamp recleaned too.

I will try maybe tonite to see how she works with the fuses pulled, i.e... the front pulled/ rear installed, then rear pulled/ front installed.
Doing so hopefully will isolate where the problem is. I did try with the side marker light pulled out, but no improvement,

Have not swapped flasher cans, they look different, one plastic can, other metal. but of course the turn flasher can does work fine with the right side turn. The hazard can work all for corners fine. Ill give that a go if they fit.

Note this is a 1990 Renix XJ. Fuses in driver footwell.

Will update later

Thanks for your helps!

cruiser54

Flasher units are interchangeable.

CRUISER'S MOSTLY RENIX TIPS

IMPROVING THE FUEL PUMP GROUND

JANUARY 3, 2016 CRUISER54 59 COMMENTSThe fuel pump and fuel tank sending unit ground at a sheet metal screw up behind the spare tire on an XJ, and behind the driver’s taillamp on an MJ.

Not only is a sheet metal screw a lousy way to ground things, this ground path is long and travels through some connectors that are prone to corrosion and moisture.

Locate the black wire on the HARNESS side of the fuel pump/sender 3 wire connector. Remove a 6″ length of the split loom covering. Strip back about 1/2″ of insulation from the BLACK wire.

Take your new ground wire, preferably at least 14 gauge and 12 to 18 inches long as needed, strip it about 3/4″, and wrap it around the exposed part of the harness plug wire.Solder the connection. Tape it up and reinstall the split loom covering.

At the other end of your new ground wire, add a crimp on eyelet. Attach the eyelet under a bolt that goes directly into the chassis. Be sure to clean the attaching point til shiny and apply OxGard to the contact surfaces.

djgrayxj

Note from DJ

Thanks for updating your profile!

Now on to business when did this problem with your left turn signals show up before or after U Hall attempted to wire up a trailer to your 90 XJ?

UKXJ

I thought OP said there was only one - so we can disregard the fact the hazards work.

cruiser54

There are 2 interchangeable flashers on a 1990.

This is a stone that must not be left unturned.

UKXJ

That's what I thought (although I didn't know they were interchangeable but, like I said . . .

Anyway, today I learnt that turn signals not working when headlights are on is a known bad ground symptom and that bad ground can be corrosion where the terminal is crimped on.

robsjeep

Swapped the two flash cans. Now turn signals work, but the left dash signal arrow stays on when ignition is on, bit it along with the front and rear left lights now flash when left signal lever is on.
Bit the hazards lights are now very dim on all four corners

thus I think the turn flash can was on its way out, AND there is also an issue with the left side lights (left dash light on solid green when no turn is commanded)
the marginal flash can that was used for turns could make the right side turns work, but not the left side, thus there is an issue still with the left side lights, but the swap of flash cans allows the left sides to at least flash now.
the marginal flash can that was for turns just barely can run the hazards, which had worked ok before I swapped the two flash cans

Ill get two new flash cans, then proceed to trouble shoot the left lights as the left dash arrow is staying on with ignition. But at least I have working left turn now

thanks for the help swapping the flash cans has pointed me in the right direction I think

robsjeep

Here is an update, still bad....

SYMPTOMS....
problem. when headlamp is turned on or parking light is turned on via the dash pull switch, the LEFT hand green dash signal arrow illuminates. This green signal arrow does not illuminate however IF I remove BOTH front signal bulbs when I turn on the headlamp or parking lamp The two left front signal bulbs do not turn on not even a faint glow when this green left arrow on dash is on like this.

In addition to above, the front turn signal are supposed to alternate from side signal to front signal when turn is commanded, if headlamp or parking lamp is on, and when no headlamp or parking lamp is on, then both these front signal are supposed to flash together. This is what occurs on the RIGHT side , but not on the LEFT side. On LEFT side the two front left bulbs flash together, but do so dimly, it does not matter if headlamp or parking lamp is on or off.

When the green arrow on the dash is on steady when headlamps or parking lights are on, it does go into flashing mode when LEFT signal is commanded, and but stays on solid when RIGHT signal is commanded.

When parking or head lamp is on I get no parking light on left front, it stays off.

The LEFT hand turn signal does flash a bit slower than the RIGHT signal

Hazard lights work, BUT the LEFT front hazard blink very dim compared to the RIGHT side. BOTH LEFT and RIGHT rear hazards are same brightness.

Tail lamps and tail signal lamps work correctly.


I have cleaned the bulb sockets, and refreshed the ground on the left inner fender, plus checked it for voltage drop to battery ground and it is just a few millivolts drop. So that is good.
I swapped the two relays (turn and hazard), with no change in symptoms, I bought a brand new flash can and installed in turn can socket, no change in symptoms.

I cleaned the front light harness connector located ahead of aircleaner

I am really stumped here. I still dont quite understand how the front a front side signals are suppose to work, i.e. how they are supposed to flash together when headlamp or parking lamp are off, but alternate with head lamp or parking lamp are on. Perhaps If I understood that I might be able to find the fault?

UKXJ

Must confess to finding it difficult to take in all of this. Maybe just information overload on a Monday evening - after a day at the fun factory.

1st,, the sidemarkers & turn signals aren't supposed to flash alternately, they just do, because of how they are wired. It is a single filament bulb performing 2 functions by the simple expedient of string them between the the 2 circuits: parking lights & turn signals, which means, when they are on, they flash off as the turn signal comes on. That's why I suggested (back in the Summer?) that we forget about them for the moment. Either pull the bulbs - or disconnect them completely. We can return to them when the real issue's been resolved.

Everything you've described still suggests (at least, to me) a ground problem with the left turn signal/marker light - despite all you've done in that respect. I'm now wondering whether the problem isn't with the ground for the left indicator light in the dash..

robsjeep

Ok, SOLVED. Yes the ground was bad, but it was bad inside the socket wires. I bought a new socket and soldered it into the existing harness
In photo below you can see the harness where I cut and stripped the wires for soldering. Note the black ground wire, the copper strand are black, I cut back away from the socket as far as practical, still black, evidently water cot in at the socket and corroded the wire back a good ways, and eventually cause the wire to terminal joint in the socket to fail Prior to soldering I had to clean up these blackened copper strand using fine steel wool and electrical cleaner spray



Front signal

I suspect the water got in the wires do to loose fit of the black rubber seals on each of the three wires, even the new socket has loose fit of these rubber seals, and yes this is an off road truck that has seen water crossings, so sealing is very important. to help mitigate future water ingress I filled the rubber boats and packed the wire entry points with silicone grease


Front signal


Finally I wrapped up with plastic tape the rear of the socket to help keep water out. And note the two foam rubber seals for the lamp house to socket, the white one is the new one, a bit smaller than original, to get the tightest fit, I used booth seals together This two seal install really compresses the seals well, to help keep water out of the lamp housing. I also applied silicone grease to the seals as a further water proofing measure and used the silicone grease on the bulb base and socket terminals.



Front signal

Lamps work great now. No more funky function!!

For reference the socket I bought at ORielly Auto Parts is DORMAN Brand #85898 It is an exact replica for the stock socket. The packing states it is for FORD 1974 thru 1989 however. But is identical to that in my 1990 Jeep. There is no indication that my old one is not stock, all factory wiring, no splice prior was done.

So all is good now, that you all for the help, it took dumb me a while but several of you did say it was ground, I just never thought the problem would be hidden in the socket, as the socket ground terminal looked fine. I proved to myself by using a jumper wire from ground to the bulb base, jamming the ground wire into the socket as suggested.

Wonderful help, thanks again. So happy!