Headlight switch! that old story

[william hulbert]

OK 2nd gen gurus I have searched for days and now must ask. Working on getting the headlight switch operational again in my 01. PO spliced in a pullout type HL switch which looks to be from the 97 type rams. So what I have is power to the headlights constant. which I believe is correct. So feeding into my HL switch I have a pink and red that is hot constant. The red and green which is the largest going in should also be hot constant but is not. However if I turn on the switch the red/green becomes hot. Also the LG wire that is HL output to the dimmer in the multifunction switch is constant hot. I believe the LG should only become hot after the HL switch is pulled out the the HL illuminate position. So any input would be great and thank you for the help in advance.

 

[BarryG]

While I am unsure of the wiring colors and no longer have my 01 FSM and wiring schematics (gave them to the purchaser when I sold it) for operation. If you dont know (but probably do since it sounds like you did some research), the headlights among others are ground switched including the high beams at the multifunction switch so there is 12v+ on all the time at the bulbs just no ground until the proper selection of the switch/es.

The headlight switches for that era are a well known problem due to the lack of relays etc and all the power goes through a marginal switch with undersized wires creating a lot of heat which shortens the lifespan and increases the voltage drop to the bulbs. While you are figuring this all out it may be worth your while to add relays for the headlights. Daniel sterns lighting website has a fair amount of good info and used to have a lot more but for some reason or other he pulled some of it back. I used his stuff for a sport headlight upgrade and found him accessible and willing to impart info via phone and email. Granted it has been a while since I did that so no idea how he is now
https://www.danielsternlighting.com/tech/relays/relays.html

Sorry for no real help on your problem but good luck

 

[BigPapa]

Looks like you have a mismatch of early and late 2nd Gen wiring. I don’t find a RD/LG on the ‘01 at all but the main feed on the early is RD/LG. I’d suggest getting the correct switch, connector, and diagrams for your truck and starting over.

 

[william hulbert]

Awesome BigPapa. I appreciate the help brotha!

 

[william hulbert]

Thanks BarryG. I have the relays on their way.

 

[petersonj]

@BarryG is right on topic here. Since you now have the wiring diagram and you are into the headlight circuit, you would be very happy with the lighting performance you would gain by adding relays to the headlight circuit.

When my truck was new there was only 10.9 volts available at each headlight with the headlight switch on low beams, the engine running, and battery voltage at 14.1 volts. That equates to about 50% light output from each low beam bulb. After I added relays the voltage present at the headlight bulb raised to about 13.5 volts under the same conditions. Most bulbs are rated at 13.2 volts minimum at the bulb in order to provide 100% light output.

Since I did the relay modification when my truck was new, I am still running the original headlight switch and dimmer switch - 316,000 miles later.

- John

 

[william hulbert]

Thanks for the info John.

 

[GAmes]

You don't need to spend a bunch of money to add relays from a kit. With two standard relays and some connectors it can be done for less money. This is for a '97 with switched hot, you only need to adapt it to the switched ground you have. The jumper wire is for keeping the low beams on with the high beams. (I failed to include a diode) If you don't want that just omit that wire and diode.

 

[BigPapa]

Since you now have the wiring diagram

If you’re referring to the diagrams I posted, he’ll need more than those. I just posted those PARTS of the diagrams to show he had wires from both trucks. He’ll need more than those to get it straight.

I also run the relays and as Gary said, you can make what you need. I also run the jumper wire and diode. A bit more advice for you, put the relays where they won’t get wet and go ahead and spring for new, high temp headlight pigtails.

 

[william hulbert]

Good afternoon guys. thanks for all the help so far. It is much appreciated. Now I have one puzzling questions as I tackle day 2 of the PO's cluster ****. Before I even torn into anything the light green wire from HL switch was hot without even being plugged into the HL switch. Most HL switches I have had were powered in the position one was park/tail lights, then position 2 energized the wire from the HL switch to the MF or dimmer switch. So I would think the LG would only have power when the HL switch is in position 2 . If not then my LG wire was being back fed throw the MF switch and was constant powered. Thoughts or if someone would be so kind to test there own LG wire from HL switch that would be great. Again thanks for everything.

 

[BigPapa]

Maybe this will help. It's the pin-out for the two Headlight Switch Connectors for the 2001.

 

[petersonj]

Before I even torn into anything the light green wire from HL switch was hot without even being plugged into the HL switch.

Not to add more confusion, but I think that your 2001 headlight wiring is the same as my 2002. If this is the case, the light green wire would be hot via the 15 amp fuse, the low beam headlight and the headlight beam select switch. All of the switching is done in the ground circuit - not the positive circuit that you may be familiar with.

From the 2002 FSM. If this is not the case for your truck, then please disregard.

- John

 

[william hulbert]

Not to add more confusion, but I think that your 2001 headlight wiring is the same as my 2002. If this is the case, the light green wire would be hot via the 15 amp fuse, the low beam headlight and the headlight beam select switch. All of the switching is done in the ground circuit - not the positive circuit that you may be familiar with.

From the 2002 FSM. If this is not the case for your truck, then please disregard.

- John

View attachment 113940

thank you sir. thats what I finally needed to know!

 

[william hulbert]

Okay my cumminns gurus I have some interesting info. So i take out my whole wiring harness to fix this and some other issues. Not really that hard. My second time doing it since buying the truck. First time was just to replace the firewall insulation, ac evap , heater core, and dash. So i'm pretty good at it now. So i find that there of course is a pink/red that feeds the newer HL switches. But remember I said that I still had a 12g red/green running up to near my HL switch. I traced it all the way back to the firewall connector. On the other side leading to the PDC there is nothing. Looks like dodge may have used the same interior harness when they switched HL switch designs and just no longer powered the old red/green from the prior years. Seems like something an auto builder would do. Now as for my pink/red. It comes into the firewall then runs up to the flasher relay terminal on the fuse block then comes out to the HL switch. The pink/red are constant power so it seems to be appropriate for the 01. So i'm cleaning up everything and putting it all in new heat resistant loom. Should look great when i'm done. Thanks again for all the help.

 

[k8rr]

OK 2nd gen gurus I have searched for days and now must ask. Working on getting the headlight switch operational again in my 01. PO spliced in a pullout type HL switch which looks to be from the 97 type rams. So what I have is power to the headlights constant. which I believe is correct. So feeding into my HL switch I have a pink and red that is hot constant. The red and green which is the largest going in should also be hot constant but is not. However if I turn on the switch the red/green becomes hot. Also the LG wire that is HL output to the dimmer in the multifunction switch is constant hot. I believe the LG should only become hot after the HL switch is pulled out the the HL illuminate position. So any input would be great and thank you for the help in advance.

OK 2nd gen gurus I have searched for days and now must ask. Working on getting the headlight switch operational again in my 01. PO spliced in a pullout type HL switch which looks to be from the 97 type rams. So what I have is power to the headlights constant. which I believe is correct. So feeding into my HL switch I have a pink and red that is hot constant. The red and green which is the largest going in should also be hot constant but is not. However if I turn on the switch the red/green becomes hot. Also the LG wire that is HL output to the dimmer in the multifunction switch is constant hot. I believe the LG should only become hot after the HL switch is pulled out the the HL illuminate position. So any input would be great and thank you for the help in advance.

I fixed the problem on my "96 2500 by replacing the switch and soldering two # 14 wires to the headlight switch lug on the new switch. I then removed the quick-connect from the old wire and spliced it to the added wires. Doing this eliminated the overheating problem caused by the undersized wire and poor connection of the quick-connect.
The problem could also have been perhaps better solved by adding a relay near the headlights activated by the switch, but with a separate 12v. power circuit.