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Discussion Starter · #1 ·
After 18 months of disassembled inactivity, my car is finally getting back to a functional state. Among other things, I had all my gages tested, refurbished, & recalibrated. All new wiring harnesses under the hood, and made a few minor repairs to the dash and rear harnesses. High beam indicator and parking brake warning lamp work fine, but none of the other dash lights work. Also seems like the fuel gage is not working (worked fine when the car was disassembled). The first few times I had the car running, it seemed that the temperature gage worked fine; now it sits at about the 3/4 of the way to hot position when the car is cold.

I can see a small screw on the bracket just above the steering column wiring connector, and another one on the parking brake bracket, where it looks like some wires should ground to, but I see no wires to attach at those screws. Am I missing some ground wires? Could it be that some of the wires that I grounded to the back of the instrument cluster are supposed to go to these two screws? TIA.

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Bill Pritchard
69 SS396 Convertible
"Life is short; eat dessert first." - Ogden Nash
My low tech web page
 

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That sounds like the problem. Just looked at mine and there is a black ground wire from the wiring harness to the parking brake mount. I can't see the steering coloumn ground but if I remember right, there is supposed to be one there as well. Good Luck.
 

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When I took mine apart, the two black wires were under gauge and speedo mounting screws. Now I'm wondering if that's correct. The only gauge I'm having trouble with is TEMP. It goes full HOT when I ground the sensor lead and full COLD when open. I think that's correct. I measure the resistance of the sender and all looks good but the gauge never leaves COLD even with the resistance changing. All the other gauges work fine. I'm thinking of running a good solid ground from the TEMP gauge mount post to a Chassis ground and see if it helps.

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Dave Bradley
www.corvetteforum.net/classics/d1_bradley
'69 SS396 ragtop
'33 3W Coupe
'65 Vette BB Roadster
 

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Discussion Starter · #4 ·
An update on my car’s condition, and a little more info for (….hopefully….) some help.

Dash lights are now working thanks to a new fuse (duh). Moved the ground wires from the back of the instrument cluster to the screws on steering column brace and parking brake bracket, to no avail. Haven't delved into the fuel gage and temp gage problems yet; one problem at a time.

For those that may be able to help me out here with the lights, I’ll try to provide as much information as possible, so please pardon the length.

With the headlamp switch in the parking lamp position: both green turn signal indicator lamps on the dash are illuminated, tail lights and all side marker lamps work fine, but parking lamps do not come on.

With the headlamp switch in the full headlamp position: both green turn signal indicator lamps on the dash are illuminated, tail lights and all side marker lamps work fine, headlights work fine, but parking lamps do not come on.

With the ignition on, headlamp switch in the full headlamp position, and right turn signal switch activated: right rear turn signal blinks weakly, both green turn signal indicator lamps on the dash are illuminated, tail lights and all side marker lamps work fine, but right front turn signal does not come on.

With the ignition on, headlamp switch in the full headlamp position, and left turn signal switch activated: no turn signals in front or rear, right green turn signal indicator lamp on the dash is illuminated weakly, both parking lamps are illuminated weakly, tail lights and all side marker lamps work fine.

With the ignition on, headlamp switch off, and right turn signal switch activated: right rear turn signal works fine, neither of the green turn signal indicator lamps on the dash work, and right front turn signal does not come on.

With the ignition on, headlamp switch off, and left turn signal switch activated: left rear turn signal works fine, both green turn signal indicator lamps on the dash blink, both front turn signals blink weakly.


With the hazard flasher on, both front and rear lamps appear to work normally, and both green turn signal indicator lamps on the dash appear to work normally.

Any guesses? Headlight switch? Turn signal switch? (Both worked fine when the car was disassembled). Thanks again, and sorry for the length.


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Bill Pritchard
69 SS396 Convertible
"Life is short; eat dessert first." - Ogden Nash
My low tech web page
 

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Discussion Starter · #6 ·
OK, tonight's experiment was to disconnect the turn signal switch by unhooking the wiring connection on the steering column under the dash. I still have no parking lights, but everything else lights up just fine. Both green indicator lamps on the dash panel come on and stay on when the lights are turned on. So, it seems like the turn signal switch is not the cause of any problems.

From what I can tell on the wiring diagram in the service manual, it looks as though one bulkhead connector terminal feeds two brown wires; one for the side marker lamps, and one for the parking lamps. The side marker lamps work just fine. I unplugged one park lamp wiring connector near the voltage regulator and put a voltmeter on both wires in the connector; I have no voltage going to the parking lamps. Makes no sense to me.

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Bill Pritchard
69 SS396 Convertible
"Life is short; eat dessert first." - Ogden Nash
My low tech web page
 

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Do you have the rear parking (running) lights on? Those don't go through the front bulkhead connector.
 

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Discussion Starter · #8 ·
John,

I'm aware that the tail light wiring does not go thru the bulkhead connector on the firewall. There really doesn't seem to be much problem with the tail lights so I'm making a possibly dangerous assumption that all is well with them and the wiring going to the rear of the car.

Since my earlier post this evening, I went out and dropped the dash and took the light switch out. Checked continuity between the two brown wires that connect to the switch and the brown wire that connects to the park lamp near the voltage regulator; it is good (~0 ohms). Is there any checking I could do on the switch itself to see if it is good? Or anything else I could check? All I have is a multimeter for testing.

Your help is greatly appreciated here!!


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Bill Pritchard
69 SS396 Convertible
"Life is short; eat dessert first." - Ogden Nash
My low tech web page
 

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0 ohms is a good reading. If the rear lights are working that tells you that the switch is OK. Is it just the side lamps out or do none of the fronts work?
 

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Discussion Starter · #10 ·
The front side marker lamps work just fine, under all conditions that I've tried thus far (see my previous posts in this thread). And from what I can tell, both the front side marker lamps and the parking lamps are fed from the same terminal on the firewall bulkhead connector, so I'm really perplexed. I have also checked continuity from the park lamp pigtail connector to the bulb contacts in the sockets, and it is good (~0 ohms). I also know that the connection is good, because the hazard flashers work perfectly. It is mostly just the front turn signals and parking lamps that are screwed up.

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Bill Pritchard
69 SS396 Convertible
"Life is short; eat dessert first." - Ogden Nash
My low tech web page
 

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Bill
What about the front lamp grounds? Have you checked those. Keep reading that the front right has problems. Up until 70, the front lamps do not have a separate ground wire. They get ground from the frame. Almost unique because most of the other grounds are tied to the body. Body ground is the short small wire from battery (-) to the right inside fender. Read this. Has some ideas on how to check and or repair the front signal/running lights. Might give you a clue. http://www.chevelles.com/forum/Forum22/HTML/001873.html
 
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I read this whole thread, and it sounds like a missing ground on the front marker lamps. I think the reason the turn signal indicators glow when you turn the head lamp switch on is a feed back caused by no ground.


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www.muncie4speed.com
Gold 67
1967 Malibu, 2nd owner.
1971 Malibu, been in the family since new.
There is nothing like rowing through the gears at 7500. Stick cars are so much fun they should be a controlled substance!
 

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Discussion Starter · #13 ·
John & Wally,

Thanks for your replies. Indeed, there are no ground wires for the park lamp assemblies. On each side of the car (drivers side & passenger side) there are two ground wires coming out of the forward lamp harness. One comes directly from one of the headlamp connectors (this is plainly visible), and according to the wiring schematic, the other comes from the side marker lamp (can't see this, there's just a wire coming out of the harness wrap). My bumper is newly replated, and I undercoated the back side of it, which is where the freshly repainted park lamp housing attaches. I used new stainless screws and star lock washers to attach the park lamps to the bumper. Perhaps there's not a good ground there. I will experiment with that tonight.

EDIT: Wait, if I had no or poor ground, why would the hazard flasher work OK?

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Bill Pritchard
69 SS396 Convertible
"Life is short; eat dessert first." - Ogden Nash
My low tech web page

[This message has been edited by Bill Pritchard (edited 06-06-2002).]
 

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<BLOCKQUOTE>quote:</font><HR>Originally posted by Bill Pritchard:

EDIT: Wait, if I had no or poor ground, why would the hazard flasher work OK?
<HR></BLOCKQUOTE>

Well, most people call it the gremlins. It really has to do with GM using a 2 filament bulb and sharing different functions. I tried to explain it using a simple example at the bottom of this thread. I don't know how well I explained it but maybe it makes some sense. The frame ground problem ended in 71 when Chevy moved the front signals out of the bumper and tied them to the body ground. Jerry's method fixes it for good but it's not the way the factory did it. http://www.chevelles.com/forum/Forum22/HTML/002015.html
 

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Discussion Starter · #15 ·
<BLOCKQUOTE>quote:</font><HR>Originally posted by John_Muha:
Well, most people call it the gremlins. <HR></BLOCKQUOTE>

And I think I'm with 'most people' in this regard!! Seriously, I understand your train of thought, if not the exact reasoning. I will try different grounding tonight, and see if it helps. Thanks again for all your help.



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Bill Pritchard
69 SS396 Convertible
"Life is short; eat dessert first." - Ogden Nash
My low tech web page
 

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Discussion Starter · #16 ·
Looks like John & Wally got me on the right track! Came home and checked continuity from park lamp sockets to ground - found it very sporadic on the left side, and nonexistent on the right side. The apparent culprit? I had not fully tightened the bolts attaching the front bumper brackets to the frame, causing minimal or no electrical path from bumper to ground. Cranked down on those bolts, hooked everything up, and voila! Perfect parking lights. Left turn signal works perfectly; right one blinks in back, but not on dash or in front (probably just a bulb contact issue).

Thanks to all who provided input here. Now it's on to the gas gage and temperature gage.

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Bill Pritchard
69 SS396 Convertible
"Life is short; eat dessert first." - Ogden Nash
My low tech web page
 

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Cool stuff.
Point to note.
The battery cable ties ground to the body and block. Need a ground strap to the frame on these cars for a good return (ground) line.
 
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