robsjeep

I got a 1990 XJ, the left turn signal stopped working, when signalled the front and rear left turn lamps and the left dash turn light go on, but do not flash. The Right turn flashes normally. Hazard flashes all four corners normally. Only the left turn fails to flash, but lights turn on.
Then another symptom, when the parking or headlamps are on, the left turn signal on the dash turns on, no flash, and the left side parking lamps barely glow, super dim, but the right parking lamps glow normal.

So where should I look? Bad ground? where?

thanks!

Roler

Here the grounds for the things that seem to be involved.

@cruiser54 less vague, this one?

robsjeep

Checked the ground point in the engine bay near aircleaner, was in good shape (I have single screw on my Renix 1990 jeep) removed both front and the rear bulb and cleaned, made sure ground was good. no change.

So left signals come on, but steady with no flash. Right signal work fine. When headlamps or parking lamp turn on the left green dash turn signal comes on, but does get brighter if I turn on left signal. but no flashing. still stumped.

BruceB

Just a guess but could it be the flasher unit that has gone bad?

cruiser54

CRUISER'S MOSTLY RENIX TIPS

CONNECTOR AND RELAY/RECEPTACLE REFRESHING

OCTOBER 30, 2015 SALAD 38 COMMENTS



I suggest unplugging EVERY electrical connection in the engine bay you can find, whether engine related or not, and spraying it out with a , 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.

Revised 1-31-2016

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robsjeep

Ok, cleaned the multi pin connector near aircleaner. It was ok looking but cleaned it and no change.

Note that when the hazards flash, the two on each front corner lamps flash together, but when headlamps with hazards are on, the right side two lamps alternate flash as they should, but my left side they flash together! Left side turn signals still do not flash at all, only steady illuminated when left turn signal is made.

still stumped.

robsjeep

Removed connector to the turn switch located under dash on the column. Ohm tested switch function for left turn. Zero ohms between the Violet wire and yellow, and Light Blue wires when left turn requested. Open circuits when turn switch returned to off position. This is as it should be per factory electrical schematic.

note violet wire is from the turn flash can, and yellow goes to rear left lamp, and Light Blue to front left lamps
Also check hazard flash can wire which is brown, when hazard switch is on, the brown connects to Yellow and Light Blue as it should, when hazard switch is off brown is no longer connected to Yellow and Light Blue, as it should.

So the turn switch appears to fine. Still stumped.

Note that two days ago I removed and cleaned all the turn bulbs and sockets on left side. And Right turn signal do flash fine. What is left?

robsjeep

i studied the schematic and cant figure how the headlight being on effects the hazard lamps in front. ie the two lamps on each front side flash together when headlamps are off, but alternate flashing when headlamps on when hazards are activated. perhaps my problem is in a fault in that circuit?

cruiser54

They share a ground.

Roler

Shall I post a 'vague answer' again here, Cruiser?😉

cruiser54

Please.

robsjeep

Well I still dont understand how the shared ground with headlamps on causes the alternating flashing of front signal lamps when headlights is on.
At anyrate my problem is why the left side dont flash for turns, front and rear, but they do flash with hazards, and right turns flash. the turn switch ohm tests ok, connector at airfilter area is cleaned as is the body ground there, and I cleaned all the left turn bulbs and sockets.

wits end here

Much more complex a system than what I am used too. (1960s VW Bugs)

any advice on what else to test is appreciated.

UKXJ

If 2 lights have a poor common ground, each will ground through the other (or try to) which would usually result in the one that isn't on glowing faintly (as current passes through it from the other lamp to ground). However, the situation is complicated if one of them is a turn signal because if, due to its poor ground, it doesn't draw much current it wont be enough to make the flasher flash. A further complication is that the sidemarker doesn't have a ground at all but is strung between the the parking light and the turn signal, which means (when all working as it should) they flash with the turn signal when the lights are off but alternate with them when the lights are on..

robsjeep

The thing is that with the hazards on, all four corners flash nice and bright, but the left turn signal is on nice and bright but wont flash, just constant illumination. So I assume the ground to those bulbs is good. And I ohm tested the turn switch by pulling off its under dash connector and it tests fine same ohms on left turn contacts as right turn contacts. And there is only one turn flash can and it works fine for right side.
So I will need to contemplate some more on what might cause this behavior. I still dont understand how the alternating front turn flashing works when the headlights are on. maybe if I can understand that I might be able to better understand this circuit. This circuit is overly complex for what it needs to do, I understand my 1961 VW Bug lighting circuit, it is simple.
Anyway any learned description on how the front signals switch to alternating flashing when headlamps are on will be appreciated. I study the diagram and just dont see how that part works at all. still stumped.

UKXJ

The fact that the hazards work does suggest the ground for that bulb is good, so concentrate on the headlight ground.

I tried to explain it best I could, so I'm sorry that didn't help but an important point is a turn signal with a poor ground may well not flash because not enough current flows through the flasher contacts to cause them to open & shut (assuming you don't have a replacement electronic flasher unit).

Your Bug is simpler because (like anything of that vintage) it has neither side-markers nor hazards but, apart from the additional functions, the XJ system is pretty basic, the only oddity being the way the side-markers are made to flash; it might be worth disconnecting it (or just removing the bulb) to simplify matters while fault-finding.