2nd Gen Non-Engine/Transmission Headlight relays, now feedback through highbeams and fog lights?

[Carolina Cummins1]

Hey guys, first post here. I have a 01, I bought a relay wiring harness from suvlights.com now, the highbeams come on when I turn on the factory fogs in the low beam position. The sales rep said I need two harness, one for each side to prevent feedback through the high beams. "The factory headlight plug that isn't being used causes the feedback," sales rep.



The advice I've recieved:

-Pull fog relay and install jumper wire

-Buy another $65 harness

-Rewire harness to a +postive relay and use factory -ground to signal relays and -ground the headlights to firewall



Any help or direction would be awesome

 

[Thomas]

... -Pull fog relay and install jumper wire...

Should do it.

Take a look at the last item on this page at the world famous Dave Fritz site: http://dodgeram.org/tech/mods/electric/headlight.htm.

Pulling the relay (it functions as an interlock - normally closed - opens with high beams) will make the foglamps inoperable and should give normal headlight operation. Installing the jumper will allow foglamps to light with either low or high beams and keep the high beams off unless you select them.

 

[Carolina Cummins1]

Pulling the relay and installing a jumper is the quickest and cheapest fix. I still don't understand why the feedback?



Thanks for the information

 

[SBettencourt]

CC1,

Its not really "feedback" that is causing the problem.

The fog light relay is simply an additional switch in the fog light circuit that can only "turn on" when the high beams are OFF. The reason is, in simplest terms, that the relay coil ground is thru the hi beam filament. So when the hi beams are OFF, you turn on your fogs, the + power to the relay coil passes thru the coil to the hi filament to ground and the relay pulls in... fogs turn ON. When you have the fogs ON and then you flip the hi beams ON, + power is now on the hi beam filament but now there is + on both sides of the fog relay coil so it shuts OFF.

The whole deal is, the relay coil draws so much less current than the hi beams that it is powered on but the light filament doesn't burn.

When you put the bypass relay kit in place, you took the hi beam filament out of the path of the fog light relay and replaced it with another relay coil. Depending on the power requirement the relay, it is possible that both the fog relay AND hi beam relay get enough SERIES power to both turn ON. Now that the actual bulb load is out of the circuit it has no bearing on the operation of the "fog ligh OFF w/ hi beam" circuit.

I found that if the truck sat for a while, the lighting would work normally with the engine OFF. The 2 relays in series would not both come on trying to split 12V. Soon as I started the engine and the alternator was pumping out 14. 2V both relays could come on because they only needed about 7V each to operate.

Bypassing the fog relay takes away the part of the fog light circuit that is trying to get ground thru the hi beam circuit.



BTW- I mentioned "simplest terms" earlier because the newer Gen IIs switch the (-) side of the circuit according to my FSM diagrams. The earlier ones switch the (+) side.

 

[Carolina Cummins1]

That makes sense, because the high beams doesn't come on imediately in the low beam position it takes about 30 seconds after starting the truck. I noticed the problem cold before startup, just hot or after shutdown.



I have pulled the fog relay and everything functions normal (except fog lights). So do you also think putting the jumpers in place of the relays will work?



I'm going to try it tomorrow. Thanks everyone for the advice

 

[Thomas]

... So do you also think putting the jumpers in place of the relays will work?...

Absolutely.

The current that was causing the problem with the headlight relay was flowing through the trigger coil of the fog light relay. With the fog light relay gone, you have, as you found out, eliminated the headlight relay problem.

The fog light relay is not used in the usual manner of a relay. It does not turn the fog lamps on and off. The headlight switch is used to turn the fog lights on or off. It is a normally closed switch, opening only when high beams are selected. With the headlight switch in the fog lights on position the fog light relay "allows" the fog lights to light when low beams are selected and prevents the fog lights from lighting when high beams are selected.

The jumper takes the place of the switch in the fog light relay, "allowing" the fog lights to be turned on via the headlight switch regardles of headlight beam selected.

 

[rubberneck]

Is the removal of the fog light relay/jumper procedure the same for a sport model truck??.

 

[Carolina Cummins1]

I don't know, I'm sure the other guys could answer that question. Sorry

 

[SBettencourt]

rubberneck,

The wiring diagram does not distinguish between Sport/non sport at the fog light relay so it is sure to be working the same way.

 

[Carolina Cummins1]

The jumper worked!!!! it works pefect. Thanks



It does make me very angry that suvlights.com wouldn't tell me this information. He recommended buying another $65 harness, figures. I want give him any more business.

 

[Thomas]

Glad to hear you're up and running.

SUV Lights has given most on the TDR great service. It's a fairly small operation. The harnesses he sells are fairly generic rather than Ram-specific. I think you'll find a lot more knowledge here regarding the actual lighting circuits on our Rams than at SUV Lights.

 

[Dieselnutz]

This is a great Cheap and easy mod. Way to go guys! I removed the cover of the fog lamp relay and put a wire tie behind, holding the normally open contact closed. Reinstalled cover and tried it out. Works perfect. Thanks for the idea. Now to get the low and high beams to stay on at the same time. Anyone know how to DIY Brite box?

 

[Thomas]

... Anyone know how to DIY Brite box?

Whatever you come up with, use relays. The OEM headlight switch contacts never see more than 2 X 65 watts, Sport or non-Sport headlamps.

Here is the basic switched ground system on your Ram: https://www.turbodieselregister.com/user_gallery/displayimage.php?&photoid=15712&width=0

Here is my version of the BriteBox® with Sport lamps transplanted into a non-Sport Ram: https://www.turbodieselregister.com/user_gallery/displayimage.php?&photoid=14178&width=0

My circuit could be easily modified to create what you want.

 

[Dieselnutz]

Thanks

Thomas, Thanks for the wiring help. I will be working on it! I picked up a handful of relays at the junk yard yesterday for $2.