Rheostat Dimmer Reoccuring Problem - Helpppp!!!

[move120]

Okay so a while back, I had posted about a weird electrcal problem I had when i was in 4wd and how a light smoke came from my gauge cluster and then I had problems with my interior lights not working...

Well I traced the smoke back to a bad rheostat dimmer switch after long searching through the forums. I found a great deal on two workng switches and sent out for them...

Yesterday, the switches came and I hooked one up.. All the lights came on, worked great for one or two starts. So I thought my problem was fixed. Well I left later yesterday for the gym and afternoon and after about 5-10 mins of driving I smelled that same smell that came from the smoke (it was dark there may or may not have been that same light smoke) and all my dash lighting went out again.. The switch had burned again..

Now I have one more working switch but these things are 155 at the dealer and I am scared to put this one in before finding out why it's burning. So what could be the problem? I have had the led dash conversion for almost over a year and no problems until this one. Loose switch behind the gauge cluster? Should I go back to stock bulbs?


Help pleasee, I've yet to think of why this would happen?

 

[TheDurk]

A rheostat will burn up like that only when it is significantly overloaded. LED's are more efficient than filament bulbs, so the conversion itself is less load, unless you added a LOT of new lighting to the system. I'd say a high resistance or intermittent short is more likely, or your rewiring for the LED's added some load that should not be there.

Time to take a VOM, measure the old bulbs resistance individually, use that to calculate what the old circuit was, and compare that to what you have, both calculated and measured (although I am not sure metered resistance on an LED means anything and a filament bulb is higher resistance operating as opposed to cold). If there is a wattage rating on that rheostat, you can calculate the minimum resistance it can tolerate. This will probably not be easy to troubleshoot, unless the unwanted load is easy to identify.

 

[move120]

thanks for the response.

hmm, i can't think of any reason it would overload. I've heard possibly the ground but I haven't touched the ground.

I have also heard the option of bridging the wires? what would that entail?

 

[TheDurk]

I have no idea, but I'll guess they mean short around the rheostat so that it is out of the circuit and everything remains at maximum brightness full-time (which is what happens in my truck, because it is always on max except maybe way in the boonies in the rain).

Easiest way is probably pull connector off the rheostat and make a bridge with some 12ga. wire and two terminals (crimp-on or solder), but I would defer to someone who has actually done it at that spot. Ghetto fix would be cut both wires, strip, twist together and tape.

The bridge would mean you might then blow a fuse if there is a short that was causing the problem, but if there was a real load on there that shouldn't be there--then things will be probably be fine. I just can't guarantee that you would not then smoke the next weakest point in the system, since we have no idea what the problem is. It would be better to find and fix it.

Has anybody installed anything in your dash recently? What can happen is someone goes to install something like an iPod dock or radar detector and goes looking for a 12+ source to power it. He finds a feed to some lights in the dash and taps into it not realizing he is drawing off a rheostat at max. This probably would not blow the rheostat until someone turned the rheostat down from max--then it lets the smoke out. Of course, whatever was wired like that would only work when dash lights were on and would now be dead--any suspects?

 

[BusterScruggs]

Does the rheostat control the dash lights on a separate circuit than the gauge cluster?