HL Hell

[twodko]

Hey gang,


Man,  I've tried every suggestion forum memberS have offered to get my HL working again........zip! I installed a new dimmer switch, new HL switch, pulled the firewall plugs from the their block and used heavy duty contact cleaner on them someone here recommended. I cleaned the HL harness plug by the batt as well then I pulled all the fuses and cleaned their contacts and verified the fuses were good. I checked the ground wires attached to the rad support......clean and tight. I also pulled the harness plug off the dimmer switch and hit it with contact cleaner as well. Finally, I pulled each connector at the HL themselves and cleaned them too.
When I push the HL switch the doors open, TL and driving lights come on but the HL come on then go black again. The only things I haven't done are check for 12v on the green wire at the dimmer switch and 12v on the green and purple wires at the HL harness itself. Should there be 12v between the red and purple or from each to ground?
This is just crazy, they worked just fine before and after the resto, harnesses were not removed for the resto, and the dash light dimmer wheel works as it's supposed to.
WTF?
I'm look at those voltage points today but what else should I be eyeballing?

[Chryco Psycho]

start tracing power , the green wire should have power at the dimmer with the switch on , if not you have a problem between the headlight switch & dimmer .From the dimmer there should be power out the red or purple wires right to the headlight plugs

[twodko]

Well guys here's the status of my intermittent HL's. I turned on the HL and there is 12v between the HL switch and the dimmer. The HL came on and off so there must be 12v on the red or purple wire to the HL harness.....verified 12v off the purple wire. All of this tells me the HL switch and the dimmer are both good.

My next question is this: The dimmer switch is mounted across a body seam with seam sealer gunk over it. You'd think that the dimmer mounting screws would provide a good ground but maybe not. Should this dimmer be grounded to the body?

The next thing will be to clean the gunk off where the dimmer switch mounts to insure a good ground.

I don't know where to go from here.

[twodko]

update........I cleaned all the seam sealer gunk from under the dimmer and botled the dimmer back in place.

HL still intermittent! Dash lights, flasher, turnsignals all work as they should as do the TL.

This is really frustrating. I jiggled the harness going to the HL switch with no effect.       

[macca3441]

Dimmer switch doesn't require ground at all!
Positive power from headlight switch to centre pin in dimmer switch, and is switched through the other two pins alternatively - high and low beam.
From there, these go directly to the headlights (unless relays have been installed).
So, not only check your input into the dimmer switch, but also your outputs!

Hope this helps,


Wade

[twodko]

Thanks Wade, I've done all that. It's almost like there is a loose ground somewhere but after jiggling here and there I can't find a problem. This is making me crazy..........OK crazier.

[Chryco Psycho]

it could be a faulty contact inside the headlight switch but it should show intermittent power at the dimmer

[twodko]

I know,  I'm just baffled at this point. On another note, did you ever find a speedo?

[charger Downunder]

Is your dash cluster grounded. If you bought a repro dimmer and headlamp switch i would change them out and put the old ones in a see what happens.

[twodko]

The dash was not removed during the resto only the heater box for rebuild so no grounds were broken.. I do have the original HL switch but not the dimmer switch. This issue cropped up last year returning from a car show. We noticed an odor in the cabin while driving with the HL on. The smell was coming from my side (no it wasn't my socks) and it turned out that the area around the HL switch was warm. I shut the HL off, the smell dissipated and the dash cooled. After advice from the membership, I bought a new HL and dimmer switch. It wasn't easy but I was able to access the HL switch without removing the dash. When I pulled the HL harness plug off the switch it showed signs that it had begun to melt. The dash lights dimmer wheel plug showed no indication of any melting so I made the assumption it had to be a faulty HL switch. What else would cause such a heat buildup on the harness plug? The plug had just begun to get soft and put out the odor in the cabin when I shut the switch off. The harness plug is still in good shape and none of the wires were shorted to each other.
At this point I'm beginning to think one of the wires in the plug must not have fully seated to the new switch contacts. Crap and double crap!
My only option now is to partly pull the dash assembly out enough so I can have a real good look at the plug. Members have told me that if I unscrew(?) the speedo cable and drop the steering column down a bit I should be able to tilt the dash out and down enough to get a good look. I hope that's the case but it won't be fun.
Speaking of the speedo cable, is it attached to the gauge with a threaded collar that just needs to be backed off enough to pull the cable shaft out?

This is such a drag

[charger Downunder]

My 70 is clip on at the speedo dont know about earlier models. I would pull the dash cluster out and check that the harness plugs fit tight into the switch, check all individually a loose contact would build up heat. Put a small screw driver in the plug ends a bend the wire joiners so they will plug in tight.Check to make sure the dash cluster ground is ok. It joins earths at the steering column.

[Chryco Psycho]

you could or maybe should install relays for the headlights , this would take all the load off the headlight switch & may solve the issue

[Dino]

Something went pretty wrong back there, I would face the music and pull the cluster.  It's not that hard to do if you first remove the steering wheel and remove the two nuts holding the column to the dash and the 4 bolts holding the column to the firewall.  Also remove the radio bezel first and disconnect the battery before you start.  Be carefull with the cluster bezel as the far right bottom corner will snap off if you get stuck behind the dash pads.  Happened to me yesterday, luckily it was a clean break and you can't tell it's superglued.

I think you have a bit more damage back there than you imagine.

[flyinlow]

Craig,s hillbilly test light

[flyinlow]

I suspect a bad ground or corrosion in the circuit.

I made a hillbilly testlight out of two old headlights. Voltmeters tell you that 12vdc is present, but that is not always the hole story. Using this setup tells you that the circuit can deliver the proper amperage , 10 in this case.

[flyinlow]

Attach one lead to the + battery post, the other to the ground wire of the headlight plug on you car ( black on my 70 &73) use a blade jumper ,or nail to make contact. the lamps should be illuminated normally........ if this test is normal ,you have a good ground.  The headlights ground on the radiator support at a common point, needs to be clean metal and tight.

[flyinlow]

Next , attach one lead of the hillbilly test light to the - battery post. Turn the headlights on , test for power with the other lead at the headlight plug.....then work backwards toward the headlight switch.  You might have to disconect at the firewall gang plug, then test at the inside part of the plug.   

[flyinlow]

Might be easier to test at the dimmer switch. I f I remember right power goes from the battery .. firewall connector...headlight switch..single wire to the dimmer...then two wires  ( one for lowbeam, one for high beam) to the headlights again going thru the firewall connector.

[flyinlow]

Went back and read your post again. When you turn on the headlights do they come on for a short time and then go out?  Headlight switches have  a fast reseting circuit breaker  in them that should make the headlights flash if you have a headlight wire that has shorted to ground somewhere. There are no fuses in the headlight circuit. The taillights,sidemakers and parking lights use a different set of contacts in the headlight switch and these are fused.

Do the headlights do the same thing on high and low beam?

[twodko]

Went back and read your post again. When you turn on the headlights do they come on for a short time and then go out?  Headlight switches have  a fast reseting circuit breaker  in them that should make the headlights flash if you have a headlight wire that has shorted to ground somewhere. There are no fuses in the headlight circuit. The taillights,sidemakers and parking lights use a different set of contacts in the headlight switch and these are fused.

Do the headlights do the same thing on high and low beam?

You have described exactly whats occurring......hi beam or low beam, doesn't matter. Dino's assessment is what I believe has happened. Without pulling dash cluster initially and working underneath installing the new HL switch, I could not accurately determine if the damage was more severe than I though.
No choice now but to dive in with both feet.
Next question is if I just remove the two bolts holding the steering column to dash support, won't that drop the steering wheel/column enough to tilt the dash cluster forward? I'll prolly pull the other four bolts to minimize any PITA problems that are easy to avoid. On my 69 the instrument cluster panel does not appear to lay under the radio bezel. I guess I'll know for sure when I get the speedo cable clip pulled and the dash panel tilted out a bit....I hope that goes easily.
Thanks gentlemen for all of the help and advice you're giving me. Today is a good day for for finding gremlins.

[Dino]

Went back and read your post again. When you turn on the headlights do they come on for a short time and then go out?  Headlight switches have  a fast reseting circuit breaker  in them that should make the headlights flash if you have a headlight wire that has shorted to ground somewhere. There are no fuses in the headlight circuit. The taillights,sidemakers and parking lights use a different set of contacts in the headlight switch and these are fused.

Do the headlights do the same thing on high and low beam?

You have described exactly whats occurring......hi beam or low beam, doesn't matter. Dino's assessment is what I believe has happened. Without pulling dash cluster initially and working underneath installing the new HL switch, I could not accurately determine if the damage was more severe than I though.
No choice now but to dive in with both feet.
Next question is if I just remove the two bolts holding the steering column to dash support, won't that drop the steering wheel/column enough to tilt the dash cluster forward? I'll prolly pull the other four bolts to minimize any PITA problems that are easy to avoid. On my 69 the instrument cluster panel does not appear to lay under the radio bezel. I guess I'll know for sure when I get the speedo cable clip pulled and the dash panel tilted out a bit....I hope that goes easily.
Thanks gentlemen for all of the help and advice you're giving me. Today is a good day for for finding gremlins.

Trust me, the cluster bezel is tucked under the radio bezel, it's only a small lip but you risk breaking either bezel.  Radio bezel is just 3 screws and lifts right off.
If you undo the 2 nuts holding the column to the frame it'll drop about an inch or so which may be enough but usually is not.  The guys that can remove the cluster easily at that time probably have a 68.  Their dash pad is flat on the bottom giving them more room whereas our 69's have a lip on the bottom of the dash pad.  Even with the column all the way down it still only barely fits between upper and lower dash pads.  When you look under the dash at the column you'll see a small plate bolted onto a bigger plate, remove only the 4 bolts from the bigger plate, ignore the other two.  It'll take you 5 minutes to remove 4 bolts and 2 nuts and you will be very glad you did.  Again, be carefull with the lower right corner being stuck behind the dash pad.
When you pull the cluster slowly pull it out, left side first, just enough to undo the wiring and vacuum lines on that side.  Once removed you'll have room to pull it out further so you can disconnect the other stuff.

Good luck!   

[twodko]

Thanks Dino, will do. The radio bezel and steering column will be addressed as suggested. Can you tell me if the speedo cable lock clip is like a circ clip or just a basic slide type clip.

Finally, why are you in the great state of Michigan when I need ya here?