2nd Gen Non-Engine/Transmission Low beam & High beam in single bulb :-(

[fj40dave]

Working on an '01 headlight issue here:



Archives described the initial problem... ... headlights would not come on when going from high to low beam - replaced the multifunction swithc... ... cured it initially..... but:



Now, the low beam lights are the only ones that come on, and when you select high beam with the multifunction switch, the low beam lights get brighter.

I also do not hear/feel the high beam relay tripping on or off when high beam lights selected. (Sport Model Truck).

I also am not seeing any power to the high beam light plug's.



Really odd to have the high and low beam now only illuminating the low beam light bulb... ... ... .



Ideas... ... where to look... ... ????



Hummmmmmmm... ... . no one has any ideas on this problem... ... . dang.

 

[fj40dave]

Any ideas on why high and low beam would start only work on the low beam bulb?????

 

[AggieJustin]

Possible bad relay for high beams? Since non-Sport '01s only have a single bulb, is it possible your high beam relay has died, but the relay for low beams is still functional?



I've got a '01 service manual, so I can look up diagrams or something else if needed.

 

[B.G. Smith]

There should be 12 volts to the bulb, the switch just completes the circuit to ground, the low should go off though. Do you have a hookup on the truck which is supposed to make the low beams stay on when the highs are on?If so that may be where the problem lies. Otherwise maybe the relay. bg

 

[fj40dave]

We did have the "Bright Box" plugged in initially... ... but took it out of the circuit to eliminate that potential.

The relay idea was considered; there are three of them in the line of relays in the power/fuse box by the battery - we swapped them around (they all have the same pt # printed on them) without any remidy :-(

Trying to avaoid throwing parts at this problem like buying another light switch..... but..... maybe that's where we need to start - a new relay and switch..... hummmm.

There's a lot of threads on the multifunction switch, but nothing on this kind of single bulb/low & bright problem... ... jeez, hate being the guinea pig on electrical issues :-(

 

[B.G. Smith]

Don't believe it can be the switch as it only has one contact that turns the lights on, the switching is done in the multifunction switch. Do you have quad head lights or are the hi/lo filaments both in one bulb? The quad setup has a high beam relay in the pdc. bg

 

[fj40dave]

We have the quad set-up... ... . which has me thinking maybe the replacement multifunction switch part number might be different for the non-quad vs quad model?

We should check and make sure the multifunction switch is for the quad it appears.



We do have the relay for the high beam in the PDC.



And..... sounds like the on/off switch couldn't be the problem then..... eliminates that part needing to be replaced.

 

[B.G. Smith]

There is a fuse in the pdc that powers the quad high beam relay, in 99 manual it is "E". bg

 

[fj40dave]

Fuse "E"... ... didn't know that... ... !!!!!!!

Gonna check that out next!

 

[B.G. Smith]

Fuse "E"... ... didn't know that... ... !!!!!!!

Gonna check that out next!

Sorry but "E" don't mean much inside the PDC. I just looked at mine, the fuse is one of the very small ones in the left hand corner as you lean over the fender, it is the fifth one down from the engine side. bg