I'm having an intermittent electrical problem with my "90 vert that is driving me nuts! Off and on, the following items go dead: LH window, RH window, ALL courtesy lights, Bose radio. Right now, they"re all dead. Consulting my FSM, it seems that these items share one or more common circuits. Unfortunately, I'm not savvy enuf to pinpoint the problem. I sure wud appreciate it if someone cud point me in the right direction... Tks...

 

Check the grounds on the back of the bell housing, drivers side.

Usually held in place with one of the bell housing bolts.

 

I'll do it tomorow. Tksalot.....

 

Check the fuse or fuseable link from the battery to the ignition switch. When you get no power use a voltmeter to see if the fuse or fuseable link has 12v on both of its connections. You can get a decent digital test meter from Harbor Freight for $8.

 

Thought I'd let you know the situation has changed a little. It now keeps blowing the 15 amp fuse in the Courtesy Lights circuit. Seems to me we're now talking about a short, vice a ground problem. Also, the problem has progressed from intermittent to constant. What approach wud you take to isolate the ground? Thanks....

 

The first thing I would check is the door switches.

Switches can short out.

Also check the harness that runs through the door to the dash.

Constantly opening and closing the door can eventually chafe the wiring and cause a short as well.

And one last thing to check is the dimmer switch.

Turning it all the way to the left turns the lights on. It could be bad.

Also hook up a 12 volt test light across the fuse socket (in place of the fuse).

Make sure your 'dimmer' switch is turned fully to the right.

Once you've isolated the short, the light should go out, or at the very least dim.

I made a light using an old trailer marker that I had lying around, to help me fix a short in my dash and tail lights.

Keep in mind that your rear hatch switch is also tied into the light circuit.

 

Thanks. You've given me a lot of tips here. I'll let you know how it comes out. If you have any other brainstorms, I'm all ears... Keith

 

Okay - I'm probably over-imposing on you at this point and just tell me to buzz off, if I am. I got one of those "cable trackers" (this one from China) and hooked it up per the directions. When I test it, per the instructions, it seems to be working ok. However, when I scan the wires in the circuit, I get nothing, nada. Question: Have you ever heard of the fuseblock, itself, ever having a short? If that were to happen in my case, I wouldn't detect anything by scanning the wires. It would be a new one on me.

 

What is a cable tracker?

 

It's an electronic device consisting of a sender unit and a receiver unit. It's hooked into the electrical system and is supposed to track the emissions from the live wire up to the point of the ground. Snapon tools makes one for about $200, but I went the less expensive route. I'm going to try to get another cheapie and hook it up just to see if the one I'm using is defective. If you google cable tracker you should get more info. Regards... Keith

 

Yes, you can have a short in the fuse panel.

The wire coating can shrink from the connection over time and wires can short together on the back side.

Remove the panels under the dash on the passenger side to get access to the fuse block.

Hook a test light across the fuse socket for the courtesy lights then start checking the harness. You'll probably have to unwrap it a ways to be able to get to the wires.

Inspect the wires, with the light hooked up to the fuse, by pulling them apart from each other. If the light goes out or dims, then you know that the short is between the wires on block.

You'll need to look at them really well to see which ones are touching and the condition of the coatings.

I wish I could be more specific, but chasing down a short can be a PITA.

I was actually surprised when I fixed the short in my lights, because the light only slightly dimmed when I found where the short was.

Probably because the filaments in the bulbs provided a path to ground to keep the test light lit.

Hope this helps.

 

Just as an update.

I looked up 'Cable Tracker' and I can tell you that the problem with this type of detector is that NOTHING can be 'in circuit'.

That means, for example, if you are testing the courtesy lights, then the bulbs can not be in the circuit.

These types of testers assume that the wire you are testing is not 'terminated' at either end.

You have a 'transmitter' and 'receiver' that is connected to each end of the wire.

If you have no signal at the receiver end of the wire, then the wire is probably shorted.

If you do have a signal, then the wire is probably fine.

The unfortunate thing about testing automotive circuits is that you would have to test for a signal at every bulb socket to check for the short by hooking up the 'transmitter' at the fuse socket and going around the car removing every bulb, one at a time, to test for signal.

Not an impossibility, just a pain.

 

Ok, thanks for the addnl info. BTW, this is a GREAT video which explains how the SNAP-ON cable tracker works. http://www.youtube.com/watch?v=NC0YIk4Z85A. Keith

 

Although they are using an 'RF' type of tracer, the procedure is still the same.

You have to disconnect or remove the bulbs, in the case of the courtesy lights, in order to trace down the location of the short.

The other type of tester, that I found on the Google search, was a 'tone generator' that works by isolating which part of the circuit has the short. But it doesn't pin point the exact location.

If you have the RF type, then tracing the short down to it's exact location should be easier.

Either way, it can still be a PITA.

 

Ur rite, it's a PITA. I have the RH side of the dash apart now, unhooked the glove box light and RH footwell light and now everything works except the LH window. I'm going to leave those two lights unhooked and go from here. I replaced the LH window switch with same result. RH works, LH doesn't. I have a new LH window motor and have the LH door panel removed. Can't figure out how to get to the window motor. What wud u do at this juncture? Tks.... Keith

 

From another thread:

'94z07fx3
CF Senior Member


My Corvette Photos
Member Since: Dec 2006



remove:
interior door panel
aluminum accessory panel
two regulator bolts on top of door
two regulator bolts on bottom of door
regulator to glass bolts
***tape window to door with window raised so that the glass can't fall into the door
regulator assembly from door
drill out the rivits that hold the old motor to the regulator

replace the rivits with flat headed bolts so that there is no clearance issue with window or use metal brake line and a line flare die to make your own rivits

install is reverse of removal

fiddle with adjustment to keep the leaks and wind noise out while keeping the window low enough not to smack the paintwork for the next week or so then put the panel back on.


Thanks to 94z07fx3...

 

Keith, given that it's on the same circuit, you might want to look at the light on the inside of the console door. I found a broken wire inside, where the hinge is at the rear corner. That can blow a fuse, definitely. I had to take the console door off and work on it at the table.

Thought this might help.


Mike
'90 'vert

 

Mike.
Thanks. I think I found the problem and it was the glove box light. All that work for such a petty light. I didn't need a glovebox light in the first place. Everything's back on and working.. (also installed a new LH window motor - that was FUNNNNN) Keith