Purchased '86 in November, and all of the electrical systems worked... until last week

The Ctsy/Clk fuse blew, and I replaced the fuse to find that everything worked fine. I was hopeful that the problem was fixed. The fuse blew again on my way to work the next day. I replaced it at work and everything worked until I got home, and then puff! One of the hood lights worked intermittently, so I disconnected the connectors for both of them. I checked to be sure that nothing had gotten into the cigarette lighter. I replaced the fuse and everything worked again. I operated the switches for the door lights, the visor vanity lights, and the glove box light. The radio worked, as well as the heater controls. (The antenna was removed by the previous owner so I couldn't tell if that is working) I again replaced the fuse.

The fuse was good for a round trip back and forth from work. I was hopeful. Tonight on a trip to the store the fuse blew again!

I've examined the wiring diagrams in the shop manual (and electrical supplement) but how do you hunt down a short when everything works when I replace the fuse?

Any suggestions are welcome.
Ed

 

You can't fix something that has nothing wrong with it! Now of course you have something wrong, an intermittent short circuit. It would be easier if the circuit would stay shorted, then you would have a chance to find it. The ctsy/clk fuse unfortunately powers a lot of stuff. Look in the first pages of the electrical diagnosis manual, 8a-ll-3 in my 87 book. The circuits powered by the ctsy/clk fuse are shown. I would look at the most likely circuits, ones where power wires are flexed, like the wires in each door that power the door map lights and go through the door frame and the door . Flexed wires have their insulation abraded and eventually bare wire shows and can short against metal which is ground. Another suspect is the antenna circuit since the motor is gone and the wire to the motor is hot all the time. Unplug the antenna relay and you interrupt the power going to the wire under the car that ends where the antenna is or used to be. If the fuse blowing stops, the antenna motor wire was likely the culprit. It will help too to trace each power wire to each device and observe the condition of the wire insulation and if they go through any punched holes in metal bulkheads. Good luck, you are going to need a boatload! If I can help any further, PM me or post in this thread.

 

I had a short in my Blazer, it was intermittent at first and then it would blow the fuse as soon as I replaced it. At that point, I bought a small buzzer from radio shack and put it across the fuse contacts and it buzzed steadily. I went around the car moving wires until the buzzing stopped and found my short.

 

Good luck! I chased a short on my 86 forever. Finally found it after much searching.

 

I'll remove the antenna relay in the morning and keep my fingers crossed!! I love the buzzer technique!! maybe I won't need to use it.

Thanks for the advice.

Ed

 

I like the buzzer idea, too. Since your fuse keeps your radio alive, turn up the music and start wiggling wires/connections/switches etc. You may get lucky.

 

Hi Agent:
Your great idea about leaving the radio on and poking at the wires occured to me too! I didn't use the car today, but will continue my search as soon as possible.
Thanks again,

Ed

 

is your radio factory or aftermarket? the reason i as is there are way to many people out the that put stereo in with out the proper items needed like a wiring harness to plug the factory plugs in from the radio. they just cut the wires off the plugs and start tying wires together and half a** tape up what they dont need. may have the problem right there if it is an aftermarket radio

 

Hi 85blkrose:
As far as I know, everything on the car is stock, including the radio.

I'm hoping to find a solution before I spend a weeks salary in fuses!!

Ed

 

...as an electrician, we used to take a light bulb and screw them into the fuse socket (before breakers caught on) and when there was a short, the light bulb would be bright and when there wasn't the bulb would be dim......take an old brake bulb and socket and jam it into the fuse holder and tape it securely in a place that you can see it and start your search......

 

i think it may be comming from the pwr antenna that was removed.leave off your radio and see if it pops

 

I had a 86 that keep blowing the fuse for the taillights-- What I found after a week of hunting was -- under the dash there was a large group of wires going to the firewall-- they was resting on the outer steering colum the outer wire of the bunch had a small bare spot that was shorting out. I just put a piece of inner tube between the wire and the colum -- was a easy fix once I found it. Good Luck Hope this helps

 

Pulled the power antenna relay last night. Way too cold this morning to drive it to work to check ( @12 degrees now) as that fuse takes out the heater controls!!! Burrrrr... too y
Thanks,
Ed

 

Sorry to revive this thread, but was there any luck? Day before yesterday I was "just driving" (read, standing on it) and the CD player/radio just died. The fuse was toast. As soon as I throw a new one in, it arc and blows. Have no idea how to chase it down.
Oh yeah, I know it's a no-no, but I touched a 15A in it's place (sb a 5A) with the radio off and the interior lights dimmed, so I'm figuring there's definitely a short somewhere.

Also, I noticed that my PKE isn't working but the PKE fuse is fine. Think it's related???