Dome light fuse blows

Jim Streib

https://www.flickr.com/photos/[email protected]/albums
Apr 6, 2004
564
Saint Louis, MO USA
It only happens when cranking. I took the dome light down and checked for grounds. If I have the door open with the dome light on after replacing the fuse as soon as I crank the engine over it blows. There nothing on the terminal next to the fuse either.

tom3 brings up a good things to try and if not here's something I'll throw out.

To keep from blowing fuses, take the blown fuse out and put a test light or a 12V bulb between the two fuse clips in the fuse block.

If the lighter is out of the socket and the doors are closed as well as the headlight switch not turning on the dome light, the bulb should not be lit as there should be NO current flowing. This would be something like one would do to find a battery drain between the battery post and the disconnected battery cable end. If the light is off, no drain but if it's dim to bright, then something is draining power.

If you were to open the door or turn on the headlight dome light switch or push in the lighter element then the light will come on so try this.

Now with the test light or bulb off, try cranking the motor and if there is a short which would blow a fuse if one was in there, then the light will come on.

You should be seeing the light come on.

The next test I need to know if you have an automatic or a manual.

Also too, are you dealing with, or do you know, is the wiring virgin and unmolested or have things been changed or added that we know nothing about right now such as added cooling fans, electric fuel pumps, changed shifter setup, or ???????. We don't need to find out later you didn't tell us something that might be important with the troubleshooting.

Jim
 

mallard

Veteran Member
Oct 3, 2013
1,961
SK, Canada
I have an issue with my 72 Z dome light fuse. Every time I start the car the fuse blows. I change it and and it doesn’t blow until I actually start the car. I’ve tried to just turn the ignition on and run through shifting like if I back out of the garage and it’s fine. Turn the headlights on it’s fine. Turn the wheel and it’s fine. Messed with the lighter and it’s fine. What else is on that circuit that will cause it to blow? When it’s blown everything else works.
Did you ever get this issue sorted out? (enquiring minds want to know)
 

slamin69

Veteran Member
Mar 6, 2016
121
langhorne pa
Well it seems that I found the problem. For some reason someone saw a plug that looked like it went on the kick down switch (same type) as the clock and plugged it on. That’s why when I tried to start the car and depressed the gas peddle the fuse would blow. Now it seems I have another problem. I have 2 wires that go down to the kick down solenoid on the trans (black and orange) I believe they are supposed to be tan and orange. Does anybody happen to know how this is wired from the switch. I don’t have a hole in the fire wall where the harness would go through which I find strange cause I know the car is all original and definitely a true Z28
 

Dave Taylor

Member
Jul 28, 2021
37
power for the dome comes from the heat lamp switch, try replacing the switch, I have seen the rheostat in those switches cause all sorts of issues, when we got or 81 well nothing worked in the car but it starting and running, I replaced the the whole electric sys with a easy wire kit, when that was done still no dome light, and after a real close insp on the pin switches replacing all that wire, a new dome light assy, I found a small crack in the headlight switch and while screwing with it doin the old tug twist wiggle check, it started working so, I replaced the switch problem solved, evidently these switches have a tendency to crack near the left side as you look at the front of it............... worth looking into there cheap and easy to swap out
 

slamin69

Veteran Member
Mar 6, 2016
121
langhorne pa
power for the dome comes from the heat lamp switch, try replacing the switch, I have seen the rheostat in those switches cause all sorts of issues, when we got or 81 well nothing worked in the car but it starting and running, I replaced the the whole electric sys with a easy wire kit, when that was done still no dome light, and after a real close insp on the pin switches replacing all that wire, a new dome light assy, I found a small crack in the headlight switch and while screwing with it doin the old tug twist wiggle check, it started working so, I replaced the switch problem solved, evidently these switches have a tendency to crack near the left side as you look at the front of it............... worth looking into there cheap and easy to swap out
I found the problem with the fuse. The guy that wired the ca put the clock connector on the kickdown switch so whe I went to start it and pressed th gas peddle down it would short th circuit
 

autobahn

Member
Jun 8, 2005
60
55963
Have you checked your grounding engine to body. while cranking you are getting a ground thru your dome light circuit .going out to my shop now will look at my 79 wire diagram see what I can see
 

slamin69

Veteran Member
Mar 6, 2016
121
langhorne pa
Have you checked your grounding engine to body. while cranking you are getting a ground thru your dome light circuit .going out to my shop now will look at my 79 wire diagram see what I can see
Hey thanks. But I found the problem. The person that wired it put the clock connector to the kickdown switch. Causing a direct short
 




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