Archived Low beams came on then went off, never to return

[TboneMan]

I just did the sport headlight conversion using the SUV Lights wire harnesses.



suvlights.com Dodge Ram (Sport Headlights) Super Heavy Duty Conversion Harness w/4 relays 9004



It worked great for 3 days. I started the truck to come home from work this evening and turned on the headlights. The low beams came on (as witnessed from the tailgate of the vehicle in front of me), they stayed on for a second or two, then they went off.



High beams work! Fogs work. No Low bean however.



It appears as though the fuses for the head lights are right/left vs hi/low, so that's not it. I've checked the fuses in the SUV wire harness, they are ok (beside they are independent, the would go out at the same time).



Is there a fuse I'm missing?



Could the multifunction switch have gone bad? (about 8 months old).

 

[ttbird]

Try switching the relays on the side that is not working, should be four relays, two for each side, one low beams the other high. This is a long shot since both low beams are not working but you need to start sonewhere. Also check all your connections on the new harness.

 

[Mishkaya]

I would guess you have an issue with the relays or the harness itself. Easiest way to check is to swap relays as mentioned earlier. If this does not work you can remove the harness from the 9007 bulb (I think), reconnect the original socket back to the headlight on that bulb and see if it works. If it does the problem is most definitely with the harness. I had a harness from them that would only light up the low beams, not the high; problem was with the harness itself...

 

[TboneMan]

Well, I disconnected the harness on one side and installed a spare 9004 and wallah... both the high and low beams work when directly plugged into the trucks circuit (i. e. , nothing wrong with the truck) .

I tried switching the relays and again, only high beams.

There's something wrong with the low beam side of the harness.

I hope I don't have to take that the entire thing apart. I won't be happy. But right now, I stuck, I can use the truck unless it is daylight.

 

[Mishkaya]

There have been a few threads on this forum in the past dealing with issues with the wiring harness from SUVlights. Might want to give them a call and see what they have to say...

Sorry for your trouble. :{

 

[Joe Mc]

Yes call SUVlights and do let us know if they stand behind their product. I'm sure I'm not the only one wanting to do this conversion at some point.

 

[TboneMan]

Ok, here's the scoop. I brought my multimeter home from work and began continuity checks. There is a small black plastic module on the harnesses in addition to the relays. This module had a screw on the back so I opened it and found a small circuit board. When I open the box, the back of the board (the side with the solders) was exposed. I started to run the continuity checks from the connector end to the solder ends. Low and behold, there was a break. I removed the board from the other half of the box and notice that a resistor between two diodes was FRIED (literally).



Finding this I called SUV lights and talked to one of their reps. He actually was quite helpful and offered to send me a new module. He did caution me that some vehicle models need higher capacity resistors than others. In addition to the new modules, he is sending me two ceramic resistors that I will repair the original modules with. He stated that the ceramic resistors should help prevent a re-occurrence of the problem. I'll enjoy playing with such things so I'll take on this job.



I suspect the difference between last nights episode and other times I've had the headlights on, is my grid heater was running full bore when I turned the lights on. Since these harnesses are connected directly to the battery, that the resister couldn't handle the load draw.



He also gave me some advise on how to reconfigure the harness to bypass this module. The problem is I'd have to remove the entire light assembly to do this (that ain't happen any time soon).



So the plan:

1) Wait for the new modules and ceramic resistors

2) I've disconnected the harness from the OEM 9004 socket and plugged it into the 9004 lamp in the fixture. (the reflectors are designed for this in terms of light distribution, but it is better than nothing).

3) When they arrive, put the new modules in and wait a minute or two before turning the headlight on when starting the engine in cold weather.

4) Quickly repair the other modules with the ceramic resistors and put them in service.

5) Hope that works.



In an emergency, pull over and do #2. Then find the time to rewire the harness.

 

[Mishkaya]

Thanks for the update. Let us know how things work out in the long run!