Electrical Question

[turismo177]

Folks, A quick question on tracking down an electrical short. My 20 amp courtesy/clock fuse keeps blowing. I thought I had the problem traced to a bad relay box in the steering column (replaced it) but the problem keeps happening. I looked in the repair manual and there are several circuits running off of this fuse to include:

*Door buzzer
*Radio
*Power Antenna
*Power door locks
*Dome light
*Courtesy light
*Theft deterent system
*Glove box light
* Horn
Etc.

Is the best way to figure out what is causing the problem to just start disconnecting things until the fuse quits blowing? At least that's what I'm thinking. I'm hoping someone else might have had this problem. I was thinking the dome light and door buzzer as the most likely suspects and starting there.

Thanks
Terry

 

[76okievette]

In my 76 it was the alarm system that casued it but I am pretty sure the wiring is different, but you might want to check that also.

 

[Sensei]

Does the fuse blow instantly, or does it take a while?

 

[turismo177]

It was blowing instantly but now it takes a little while. Perhaps 10-15 minutes.

Thanks

 

[mkapp7879]

Does your power antenna work correctly? Sometimes when the nylon leader breaks and the mast becomes stuck the motor keeps running, and running......

 

[turismo177]

Aren't electrical problems fun. I discovered something else tonight. I put a new fuse in and turned everything on that the circuit runs. I had the drivers door open. The fuse held securely. Then I closed the door lightly and the fuse still held. I then closed the door hard and poof the fuse blew. I thought then there must be something in the door causing the problem.

I removed the inside door cover and found the wire to the theft alarm was already disconnected so I eliminated that as a cause.

I then removed the wire from the automatic door locks and everything seemed fine. I put a new fuse in and it blew instantly with the door open so I must have disturbed something in the door causing the problem. Still haven't found what the problem might be and would appreciate any advise.

Note, the electric windows work fine, with no problems as they are not on this circuit. The only electrical I see in the door are the alarm, power door locks, and the window. Am I missing something?

Thanks
Terry

 

[petes74ttop]

Electrical Nightmare!

On my 74 the front door jam switch controls the courtesy lights and the key buzzer, when you open the door the switch makes the circut to ground could that switch be shorting out? Just a guess since yours is a different year. PG.

 

[bill81vette]

Did you look at the wires themselves???
check inside the rubber boot,between the door and the body.
also try following the wires as much as possible back to the fuse block

good luck!!!

 

[wishuwerehere82]

A fuse blowing instantly at the slam of the door indicates that there is a direct short to the body ground somewhere in the area of the door/window/power lock wiring harness. Not a loose wire, but a chafing of insulation that is making direct contact to the door frame. I would take as much of the wire harness loose from the door and inspect it for worn or cracked insulation and tape it up to prevent it from further chafing.

 

[Peer81]

You have to work the other way around or if you have enough fuses it doesn't matter. When you have everything disconnected just connect one part at the time and check. Then you'll find the short circuit by itself. And what wishuwerehere82 said, it indicates to be a problem in the door. Maybe you can disconnect the wiring in the door and take it out to check it compleetly. If not, check at the bends or where it is connected to another material (metal like). After so many years a wire could be open and only connecting to ground when you slam the door. Good luck!

Groeten Peter

 

[rbryce]

A point to consider. If the door switch is making a connection to ground to activate the lights, buzzer, etc, shorting this wire will not blow the fuse, it will simply turn on those items. You need to start looking for a wire that is supplying power to the load and is shorting before the load, not after the load.