Handful of gremlins

[withoutremorse42]

I've got a few electronics gremlins I've been battling and am hoping for some help in trobleshooting them. I'll try to give you as much info as I can on what I've checked so far, and any help anyone can provide will be greatly appreciated. I'm no electronics expert!! I have the Haynes manual and the factory assembly manual but havent found enough info in either to help me finish these up.

1980 L48, t-350

1. High beams. When I click on the high beams at the steering column with the blinker/high beam selector/cruise control lever, all running/dash lights stay on but low beams go off, high beams don't come on. No voltage drop or raise at the voltmeter. If I jiggle the lever, my parking brake light flashes on and off. No voltage reading at the high beams, bulbs are good. I suppose on this one I'm just looking to hear if anyone else has had this problem and if these symptoms indicate a bad switch at the column or not.

2. Overhead light is always on. Is this wired to both door jamb switches? Can I bypass these or do I have to replace them? Is this also wired to the headlight/dimmer switch? Have briefly considered simply adding a push button switch up top.

3. Rear defrost. There is power to the switch. Switch seems to test well, it has continuity on some connections in one setting, then power to other connections in another setting. Back at the window, the actual black strip stuff on the window has continuity, the ground is clean as well. The large purple wire coming off of the back window and going into that mysterious box on the RH side of the rear storage compartment has continuity from the box to the window. I have no idea how to test the magic box, nor where to find a replacement. NAPA and affiliates couldn't track one down, corvetteamerica doesn't seem to have one.

Am I better off just rewiring this on a toggle switch to exclude the timer (which I think that box is) with an inline fuse? How big of wire should i use if I go this route? Same for fuse.. 30A? I have no problem remembering to turn stuff off when appropriate. I hate to start bubba-ing though. The defrost worked when I bought the car 4 months or so ago.

4. What is with the "vapor canister"? By the name it seems obvious it has something to do with fuel vapors, mine seems to be partially to mostly disconnected. Is it a necessary item? I don't remember having it in my last vette. Can it be bypassed/removed safely? Are there any precautions or necessary steps to take to close off whatever might still be connected? Looks like most of the vaccum lines up front were ripped off of it.

Thanks for any/all help!
Jens

 

[TimAT]

reading your posts, I suggest you invest in a good wiring diagram. "Doc Rebuild, Ecklers, Corvette America, you name it- just aboiut all the decent vendors have them.

 

[Rodney Gold]

You can find quite good wiring diagrams for your vette at
Index of /johdotukset

 

[DeeVeeEight]

I've got a few electronics gremlins I've been battling and am hoping for some help in trobleshooting them. I'll try to give you as much info as I can on what I've checked so far, and any help anyone can provide will be greatly appreciated. I'm no electronics expert!! I have the Haynes manual and the factory assembly manual but havent found enough info in either to help me finish these up.

1980 L48, t-350

1. High beams. When I click on the high beams at the steering column with the blinker/high beam selector/cruise control lever, all running/dash lights stay on but low beams go off, high beams don't come on. No voltage drop or raise at the voltmeter. If I jiggle the lever, my parking brake light flashes on and off. No voltage reading at the high beams, bulbs are good. I suppose on this one I'm just looking to hear if anyone else has had this problem and if these symptoms indicate a bad switch at the column or not.

2. Overhead light is always on. Is this wired to both door jamb switches? Can I bypass these or do I have to replace them? Is this also wired to the headlight/dimmer switch? Have briefly considered simply adding a push button switch up top.

3. Rear defrost. There is power to the switch. Switch seems to test well, it has continuity on some connections in one setting, then power to other connections in another setting. Back at the window, the actual black strip stuff on the window has continuity, the ground is clean as well. The large purple wire coming off of the back window and going into that mysterious box on the RH side of the rear storage compartment has continuity from the box to the window. I have no idea how to test the magic box, nor where to find a replacement. NAPA and affiliates couldn't track one down, corvetteamerica doesn't seem to have one.

Am I better off just rewiring this on a toggle switch to exclude the timer (which I think that box is) with an inline fuse? How big of wire should i use if I go this route? Same for fuse.. 30A? I have no problem remembering to turn stuff off when appropriate. I hate to start bubba-ing though. The defrost worked when I bought the car 4 months or so ago.

4. What is with the "vapor canister"? By the name it seems obvious it has something to do with fuel vapors, mine seems to be partially to mostly disconnected. Is it a necessary item? I don't remember having it in my last vette. Can it be bypassed/removed safely? Are there any precautions or necessary steps to take to close off whatever might still be connected? Looks like most of the vaccum lines up front were ripped off of it.

Thanks for any/all help!
Jens

#1. Interesting problem. Check for aftermarket wiring kit relays. I agree that the switch in the column is suspect.

#2. Yes the dome light is activated by the headlight switch. Try rotating the shaft/knob on the headlight switch, it is also a dimmer switch for your dash lights at night. Also the door jamb switches activate the dome light by completing the circuit to ground, see if the door jamb switches move freely and/or if the wire has fallen off of the back of the switch, you can see this by removing the kick panel cover.

#3. Keep checking for continuity. I am not familiar with the magic box. The fact that it worked 4 months ago is promising.

#4. The vapor canister collects gas vapors from the carburetor/fuel system and sends them back to the gas tank. Best to keep it intact IMO.

Tough to troubleshoot electricals remotely but it sounds like you have what it needs to get the job done.

 

[withoutremorse42]

I replaced the dash switch for the rear defrost to no avail. I replaced the "magic box" aka the rear defrost timer/relay and i once again have defrosting.

 

[withoutremorse42]

fixed the dome light today. The timer delay box behind the glove box was bad, so i pulled the 2 white wires out of the harness and hooked them together. Now my door switches and headlight switch activate the light properly.