87 sportruck no dash lights, turn signals, windshield wipers

[Troubador530]

I just bought a 87 Shortbed 4.0 4x4 5 speed.

 

The dash lights do not work, as well as the wipers or turn signals. I replaced the ignition switch because i thought this was the issue, and the plugs looked fine, not burnt or melted.

 

This brought back my blower motor, but nothing else. The hazards flash only the driver side. I'm wondering where to check next. I'm not that great with electrical stuff and I'm stumped!

[SVPete]

The dash lights are dimmed by rotating the headlight switch. Double check that they aren't just "off" from being dimmed all the way.

[Troubador530]

Nope, they are totally dead.

[SVPete]

Power for the instrument lights goes.... park fuse (10 amp) to headlight switch to Inst Lps fuse (5 amp) to lamps.

 

Ground is located under the left hand side of the dash near the brake release handle. Go to www.cruiser54.com. Look at mostly Renix tips, number 18 for a good picture of where that is.

 

Recommend you look at everything he has and follow his tips as you work on your truck.

[Troubador530]

Do you think that a bad ground could cause all that stuff to be dead? Because its supposed to rain soon and i need those wipers!

[Megadan]

Wipers and turn signal are both controlled by the same stalk.  Sounds to me like a good place to start for those.  

FWIW, I hate wiring too, but with a voltmeter or at least a dummy light, you should be able to track down the issue.  Check the fuse block under the dash and make sure it's not destroyed by brake fluid from the clutch master cylinder.  It's a very common issue with the manual trucks as the clutch master is directly above it, and when it leaks it destroys the plastic of the fuse block.

[SVPete]

Troubador, your problems could be related or not. I believe the instrument lights would be the easiest place to start/check since you could easily check for power at the park fuse, then the instrument lights fuse. A poor/bad/missing ground could cause any direct current electrical problem. The wipers share the same ground as the instrument lights.

 

Do no panel lights illuminate including climate control lamps and your transfer case shifter light? Hopefully you have pulled a couple of bulbs and confirmed they are good.

 

To add to ImpulseRocket, the hazard switch is part of the turn signal switch. What isn't making sense is only the drivers side hazards working. That would lead me to check passenger bulbs, then clean the sockets.

 

Safety first...no hot swapping of electrical components. Turn power OFF, then disconnect/connect cables/connectors/components.

 

For turn signals, equipment condition: ignition switch in "accessory", left turn signal on, hazards off - start from turn/bu fuse verify good and power exists there with multimeter or test light. If your D/S hazards are working as you mentioned, swap the hazard flasher and turn signal flasher to see if the same conditions exist (no turn signals and D/S hazards). I would also confirm if power is there using a multimeter or test light. From there, you need to chase the power to terminal "L" on the C156 connector to the turn/hazard switch assembly. Check to ensure it is securely connected first. If you have power at terminal "L", replace the turn/hazard switch assembly.

 

Question on wipers....do you have intermittent wipers?

 

I have had two clutch master cylinders leak onto my fuse box, some of the fuses disintegrated when I tried to remove them. I certainly cleaned my fuse box to get that mess off things and remove the gunk like exists on the C101 connector.

[Troubador530]

After 2 afternoons of fiddling without a test light, i got the turn signals working except the driver tail (driver tail light is totally dead), but i still have no dash lights, tail lights, or windshield wipers.

 

I started to improve the instrument panel ground as per cruiser's tips, but i cannot locate the 8mm stud near the fuse block. I can't find any decent place to ground it. I'm stumped.

 

The fuse block is in good condition, i replaced every single fuse just to be sure.

[SVPete]

I believe the 8mm stud Cruiser is referring to one of the studs holding the parking brake mechanism to the left side of the cab. It is behind/above the kick panel next to where your left foot would be when applying the parking brake. That's where I ran my extra ground to.

 

While you were back in your tail lights, hopefully you refreshed the ground behind your drivers tail light per Cruiser's tip #1.

 

Do your Reverse lights work? Rear license plates lights work? If they do or don't it could help with diagnosis.

 

A test light or a multimeter will really help you to confirm power getting to places.

[Troubador530]

I replaced the headlight switch, and found the brown wire burnt up in the connector. So i cut it and replaced the female connector on it and stuck it back into the harness. Now when i try to turn on the headlights it blows the park fuse. I'm so confused.

 

What I haven't done is refresh the taillight ground because the screw is stripped and i have no power tools. Could this be the cause? I have had the dash all torn apart for a week now and I'm not getting anywhere.

[SVPete]

Not sure about the brown wire at this moment....pull the chime module (black or blue box on mounted on the left side of your fuse box) and see if that stops the fuse from blowing.

 

Type "chime module" in the search box on the main mj tech page. Some of the results may relate to the situation you are experiencing.

 

You can beat this.

[mikekaz1]

for a while I was intermittently blowing my park fuse, until it got to the point it was EVERY time I used the headlights I blew the park fuse.  it ended up being  my taillight harness, more precisely my license plate lights (ground and power wires) were melted and fused together, among other previous failed "repairs" by previous owners

 

.    try unplugging your tail light harness, its just behind the drivers rear tire on the inside of the frame rail, then replace the park fuse and try turning the headlight switch on. this will atleast  isolate issues to before or after the tail light harness.

[Troubador530]

With the plug disconnected it still blows the fuse. But on another note I noticed that the wire for the backup lights (brown and white) before the plug is just hanging there.

 

I can't figure out where it goes. There is no slot for it in the plug. The license plate light wires are a mess, when i get some wire i will re do all of those. I have a hard time believing that a short way back here could affect dash lights and wipers.

[tugalo]

I would suggest tackling the light issue first.  According to the 88 wiring manual, there is no brown wire going into the headlight switch, there is a tan wire on the output side of the switch that feeds power to the headlights, the beam select switch,  and the headlight delay module if you have one. 

 

The PARK fuse feeds power to the headlight switch and the  switch then sends power to the rear taillights, the license light, and the INST LPS fuse. 

 

Pull the INST LPS fuse and see if the PARK fuse still blows.  If not, then the short is in the instrument panel on the output side of the headlight switch.  If it still blows, you could have a bad headlight switch.

 

Make sure that you connected the ground lug to the headlight switch.

 

Fix the instrument panel ground and the rear lighting ground.  Until you know that your grounds are good, you are shooting in the dark.

[Troubador530]

I have refreshed the tail light ground and the dash ground. The previous owner really beat the crap out of this thing, and the whole underside is just covered in oil, dirt, clay and anything you can imagine.

 

I'm probably going to have to trace the rear lighting circut all the way forward to check for exposed wires and such. But I'm still wondering if a short in the tail light wiring could cause no dash/interior lights, and wipers.

[mikekaz1]

No dash / interior lights. Yes. Its all part of the parking lamp circuit. Wipers, probably not.

[Troubador530]

I found out that if i pull the headlight switch all the way on, then put in the fuse, all of my exterior lights work, but if i put the fuse in first and then pull the switch out, it blows as soon as i hit the first click.

[mikekaz1]

I'd bet its an interior short in the throw of the plunger. I'd replace that headlight switch.

[Troubador530]

Well i have two switches, could i have blown up the new switch when i replaced it before fixing some of the connections?

[Troubador530]

I have tried 3 different headlight switches, it blows the park fuse on the first click. If i pull it out all the way, then insert the fuse, all the lights work, including sidemarkers and dash lights which didnt work before replacing one of the front park light sockets. So I'm making progress? I think??

[tugalo]

Pull the INST LPS fuse and see if the PARK fuse still blows.  If it does, the problem is probably in the wiring from the headlight switch to the front lighting, since you have already tried disconnecting the rear lighting.      If it doesn't blow, your problem is in the instrument panel or the wiring to it. 

 

Find and disconnect the front wiring and see if the PARK fuse blows.  If it doesn't, your problem is in the front lighting or the wiring feeding it.

 

If it does blow, disconnect the front lighting the way you did the rears and try it again.  If it still blows, remove all l the bulbs from the front lighting (turn sigs, marker lights), and the the PARK fuse. Get a multimeter and set it on the lowest ohm range it allows. Put one lead on Pin R of the headlight switch HARNESS and the other lead to ground.  if you read a low value, you have a short in one of the blue wires feeding the front.

 

the other possibilties are the clock, the audio alarm,  or the headlight switch itself.  Junk yard to get another switch from a Cherokee if required.  My money is on the headlight switch.

[Troubador530]

I have pulled the inst. lamps fuse and it still blows. I will try disconnecting the front lights tomorrow, the plug is near the front of the air box right?

 

Also i have tried 2 brand new headlight switches. All of them with the same result.

[Troubador530]

Okay, I have unplugged all bulbs in the front and it still blows.

 

I did find that there is a little connector hanging under the truck that i think goes to the transmission for the reverse lights, it looks like it has been melted beyond recognition, it has a few wires into a plug with a jumper between two of the pins. And two wires short of the connector with male spade connectors on them.

 

I'm sorry to have so many questions, I'm new to commanches, and this is supposed to be my daily, but I can't seem to figure out this short. Its only on the running light portion of the headlight switch.

[SVPete]

By "audio alarm", did you mean "chime module"?

[Eagle]

I'm sorry to have so many questions, I'm new to commanches, and this is supposed to be my daily, but I can't seem to figure out this short. Its only on the running light portion of the headlight switch.

 

Don't worry about being new to Comanches. Most older vehicles develop wiring gremlins (check out Chevy brake lights some time!), and it's always a guessing game to isolate the problem.

 

Basically, if you have disconnected all the lights and it still blows the fuse when you pull the switch to the parking lights position, but doesn't blow the fuse if the switch is full on, it's not the lights and it's not the wiring between the switch and the lights. So we have to ask -- what's left? I have three '88s (two Comanches and a Cherokee), and I can't think of anything that would be on with the parking lights that would NOT be on with the headlights.

 

Yours is a Sportruck, right? With the idiot lights instead of gauges? Do you know if it has a headlight delay module? That would not have been standard on a Sportruck (I think), but might have been an option.