I just bought this project from a guy that has most everything working, except the turn signals and wipers. #5 fuse pops as soon as I turn the ignition on. The brake lamp in the dash lights up, and I don't know if that's related or not. Windshield wipers aren't working, but the fuse is good. I have a Haynes manual that seems to not have much on the 85 thru 87 wiring. Does anyone have a good diagram of the wiring harness, or if you have had this problem, can you steer me towards where I should check? The previous owner thought it may be the harness in the column, or the ignition switch.

 

I bought a 91 with no wipers. I had power to the motor, so I bought a new motor and it fixed that. There is a grounded wire someplace if the fuse blows. I've seen trailer connectors corrode and ground out, I've seen bulb filliments burn together and pop fuses, and I've seen bad sockets corrode and ground out. Pull every bulb, visually check them, check the pig tails. Use an ohm meter and check for shorted wires. Brake light on the dash usually means there is low fluid, or the park brake is on, or a bad sensor. Gonna take some digging.

 

I was thinking the park brake could even be the short, so I gave it a quick look earlier. It had one plug on the switch. It looks like there should be another plug, that may take care of the dash light. I'll be under the rear tomarrow looking to see if there are splices in the wiring, then on to the bulbs. Thanks.

 

the wiper motors are known for having a bad ground. it is best to try grounding the motor casing. they normally ground through the bolts but the connection can get bad with age.

is the park brake peddle all the way up? that can cause the brake light to come on. the other reason it will come on is generally a leaky brake line

do the hazard lights work? i would assume there is likely something wrong with the turn signal switch if fuse 5 blows the moment you turn the truck on if you don't have the turn signal on. you can try unplugging it at the base of steering column

 

E brake light is on when it's up or down. Hazards work. Unpluged the column and the fuse didn't blow.

 

if the hazards are working i would assume the wiring/bulbs is all good. you can test the switch if you know how to use a multi meter

 

Ain't youtube videos wonderful. I'm going to give the test part a try. Thank you!

 

All bulbs are lit. I believe I did the check correctly. Pulled the plug, and continuity is good in all positions.

 

have you tried turning the key on with the turn signal on left or right to see if a fuse still blows? it really seems like a strange issue especially if the switch tests good.

 

Got it. I unplugged the rear brake harness, and took out the signal flasher, and when I plugged the flasher back in ..pow. It had to be in the column, so I tore it apart and left the signal hanging. No pop. Put the harness back in the column, went to put the signal arm through the column and it wouldn't go in far enough for the screw to go through. The signal harness replaced by the previous owner, so I pulled it back out to have another look at it. The bottom of the harness where the arm has a notch was a v shape. The arm was in there when I took it apart so I didn't thing much about it. I notched it to match the signal arm and reassembled everything, and all is well. I think the arm was not fitting the notch and was close enough to the column that it was shorting out there.