Headlights won't go off

[Crackedback]

remove green(?) wire from the door relay and see if headlights go out. It's the wire from switch that is supposed to trigger doors opening/closing

Click the dimmer to see if the lighting swaps, from high to low with switch off.

I'd disconnect the dimmer plug and charge the violet and red wires separately. See what you get.

 

[Big O]

Thanks, that's where I'm headed next. Appreciate the support!

 

[Big O]

Dang, I was hoping it might be that headlight door switch, but I disconnected it and they still come on. I had a new set-up Bosch relay that I went ahead and installed and still headlights on. Disconnected the the wire harness from firewall in the engine bay and everything looked good but I went ahead and cleaned it up a little bit and shot some contact cleaner in it, but no change. Anyway, going under the dash at this point to start digging in there. Last time I about wedged myself in there for good, getting too old, so I think I'll pull the driver seat so at least I can lay down under there. As a side note, if in fact the bulkhead connector is fried, I haven't checked to see if or what kind of replacement there's available. Cross that bridge if I get there.

 

[Crackedback]

With everything plugged in. Disconnect the dimmer switch plug. If the lights stay on, something is hunting. That is the one location that separates the lights from power.

 

[threewood]

Not necessarily the bulkhead connector but one of the bat + wires getting hot and melting through the insulation of an adjacent wire and giving it power (headlight wiring).

Strip some insulation tape from the interior harness and inspect the wires.

 

[Big O]

Did you disconnect the headlamp door relay?

Yes.

 

[Big O]

With everything plugged in. Disconnect the dimmer switch plug. If the lights stay on, something is hunting. That is the one location that separates the lights from power.

I'll give that a shot while I'm in there.

 

[Big O]

Not necessarily the bulkhead connector but one of the bat + wires getting hot and melting through the insulation of an adjacent wire and giving it power (headlight wiring).

Strip some insulation tape from the interior harness and inspect the wires.

Thanks, I'll check that as well.

 

[Kern Dog]

check the door relay. Pretty common that they bleed energy to the other side.

Yes.....THIS is what turned out to be the problem when I installed the famous "CrackedBack" headlight relay kit a few months back. With the help of FBBO members, I found that the stock headlight door relay was in fact leaking just enough power to energize the aftermarket relays. I used a Bosch relay in place of the stock one and all is well now.

https://www.forbbodiesonly.com/mopa...ealed-headlights.213911/page-3#post-911833938

See post # 57.
***********************************************************
EDIT:
Sorry if I responded too late. This may have already been covered.

 

[devinism]

Yes.....THIS is what turned out to be the problem when I installed the famous "CrackedBack" headlight relay kit a few months back. With the help of FBBO members, I found that the stock headlight door relay was in fact leaking just enough power to energize the aftermarket relays. I used a Bosch relay in place of the stock one and all is well now.

https://www.forbbodiesonly.com/mopa...ealed-headlights.213911/page-3#post-911833938

See post # 57.
***********************************************************
EDIT:
Sorry if I responded too late. This may have already been covered.

Good to hear that there was no meltdown!

 

[Big O]

Got the connections unplugged from the engine bay side and it looks like there was some short there as a couple of the sockets looked like they shorted/melted. I'm going under the dash at this point to pull the connector out and see what additional damage there is on the inside. Looks like there are couple of people out on Ebay that sell these replacement blocks, I just need to see what all shorted on the inside. More to follow...

 

[devinism]

Got the connections unplugged from the engine bay side and it looks like there was some short there as a couple of the sockets looked like they shorted/melted. I'm going under the dash at this point to pull the connector out and see what additional damage there is on the inside. Looks like there are couple of people out on Ebay that sell these replacement blocks, I just need to see what all shorted on the inside. More to follow...

At least you're doing this at home. SOME of us had to do it on the side of the freeway (in 1980! That tells you how long we have been having these issues)

 

[Nacho-RT74]

Every step mentioned is what I told on my reply from the begining.

 

[Big O]

Every step mentioned is what I told on my reply from the begining.

and is much appreciated. Thank you.

 

[Big O]

At least you're doing this at home. SOME of us had to do it on the side of the freeway (in 1980! That tells you how long we have been having these issues)

That's for sure. I had a 72 Charger back in 1975 driving it at night and just the opposite of my problem now, the lights went completely out. Little scary driving w/no lights, ended-up being the headlight dash switch burned up. Love these Mopars!

 

[devinism]

That's for sure. I had a 72 Charger back in 1975 driving it at night and just the opposite of my problem now, the lights went completely out. Little scary driving w/no lights, ended-up being the headlight dash switch burned up. Love these Mopars!

Could be worse.....

 

[Big O]

Just a little update. I did get the bulkhead connector pulled and as I said before, on the engine bay side, there is one place where it looks like the plastic area around one side of a connection melted, but after looking at the connection inside once pulled, overall, it actually looks pretty good. I did go ahead an order another bulkhead block and am waiting on that at this point. Per Nacho's suggestion, before I pulled the bulkhead block, I did disconnect the forward lighting harness, connected the battery, and the headlights did not come on, so that confirms it's in the cab somewhere. While I'm waiting on the block, I'm opening up the applicable under dash wiring bundles and the dimmer switch in particular to see if there is any evidence of shorting upstream of the bulkhead connector. Headlight door relay has been replaced and functions, so I'm eliminating that possibility at this point. Anyway, hopefully next time I have the issue identified. Appreciate you guys hearing me out...

 

[Big O]

Well, 2-1/2 months later I've pulled the old bulkhead which 2 of the connections from the inside had melted and 3 wires had melted together. The root cause was a short in the high beam switch on the floor which I replaced. So I didn't replace the internal wiring harness, but cut back sections of the damaged wire and butt spliced and heat shrinked in sections of new wire and connectors to go into the bulkhead. The replacement sections of wire looked to be 12ga and 14ga which is what I used for the new wire. One question I have is this safe repair in this application to do this without in fact replacing the complete wiring harness?

So jumping ahead, I got everything installed yesterday and the headlights now work both on and off which solved the original problem. The new issue is, the car started but immediately died every time I fired it. I've rechecked the wiring to a couple of diagrams I have and it looks like everything is correct but I'm going to pull it again today and recheck. Does this sound like an issue in the Run circuit/connection? Keep in my mind the car was running fine before I started this repair. Anyway input on this, would be appreciated. Nacho seems to be extremely versed in the electrical side so I'm all ears at this point. Thanks!

 

[Nacho-RT74]

Yeap, sounds as a faillure on the Ign1 ( Run ) circuit. Blue wire.

If you get the BRAKE light on cluster ON ( as far emergency brake is applied ) with key in RUN and turns off while cranking, you got missed/cut that circuit somewhere between ballast and ign switch plug. Since you manipulated the bulkhead, mostly sure is there. Engine harness plug could in fact got melted the alt wire, which is at a side of the ign1 wire

 

[Nacho-RT74]

About the harness fixing or replacing! I'm one of those that kind of small fixing will never require a full harness replacement, specially if the original harness tape looks to be still untouched. Those ends fixings are not hard to do. Sometimes you can refresh the full harness cutting all the old terminals and attaching new ones as far copper strands seems to be still shine when you cut them for terminals replacing job. The plastic pieces replacement with new plugs and bulkhead conector is optional too. This kind of job can get up to $100-150 ( if we include the engine bay side harnesses plugs ) but a full underdash harness is around $600.

Sure the original harness tape could hide damaged wires with melted/burnt spots, but 90% of the times the melting spots begin on the exposed ends because is where terminals are, prone to resistance created by loosen, dirty and rusty conections, specially at bulkhead.

IMHO The only harnesses which I would replace as soon they look bad are engine and NSS, due the heat and oil around, which makes to crack the wire covers and getting them hardened. But the rest of harnesses ( including forward lighting ) are fully serviceable easy to get them refreshed.