live2tune

Hello


This is my hypothesis.. I have excessive draw/low voltage some where in my low beam circuit causing the copper contacts in the headlight combination switch device to heat up distorting the small plastic assembly which houses them.. I bought a new used combi switch which was stamped with "w" which means it worked fine and installed in my car. 2 months later no low beams..

SO i took the switch apart to find this ( in the pics) the plastic being heavily distorted causing the contact to not function properly could it be the result of low voltage drop somewhere?

live2tune

http://s1323.beta.photobucket.com/us..._0474.jpg.html

mtroxel

My first thought about your scenario is: if you're pulling enough amperage to melt a switch, why isn't the fuse melting too?

live2tune

GOOD POINT. Well then maybe it's not a draw such as that. could it be that because of the contacts points and it's small 'footprint' that is actually contacting the contact patch that is creating a type of bottleneck? like a resistor? Thanks for your help!

mtroxel

Could be....but did the same thing happen to your first switch too? Or did you change the combo switch for some other reason? It's not something that commonly happens with these switches, so it's not a design flaw. I have 65 watt Osram Rallye bulbs in mine instead of the 55 watt OEM bulbs. Never had that problem.

Any chance the fuse is bigger than what the book calls for there?

If the fuse is the right size, and you've melted two switches, I'm not sure where your draw is. If this is the only switch that fried, your theory might be good.

live2tune

This has been an ongoing problem for the a year an a half or so.

the switch that came with the car failed and I bought the wrong switch to replace it and that's when I decided to fix it my self. so the switch that's in the car now has been for at least 6 months.. It failed 2 months in and i was getting frustrated so I jumped the power to the low beams from the running lights and it worked for a month or two then failed and I had to modify both contact assemblies in the switch for them to create a circuit and work properly.

I've done all I can to ensure the contacts are worthy of a good connection even lubed it up nicely with dielectric grease.

I've tamed my habits of flicking the lights on and off simultaneously as I'm turning the car on or off trying to avoid power surge or w/e it may be.. still no luck, my lights work now because of freeing up the contacts, and getting to the switch and removing it can now be done in my sleep.

however the problem must be elsewhere i can only assume.. the switch is so simple.. I just can't pin point the problem but ill check the fuse and get back to you.. I believe they are f18 f19 f20 f21

mtroxel

Google "melted headlight switch" and you'll see some horror stories. Think fire.

I'd take this seriously. Again, not sure why the fuse doesn't blow, but maybe you have a short to ground. I'd take an Ohms reading between the positive at the H7's and ground. If you show any continuity to ground there, you know you have to start working back through the wiring harness to find your short.

live2tune

Okay I will get on that thanks for the heads up. so my fuses are correct.. f18 and f19 10amp, and 20 and 21 15amp.

live2tune

so if there's any resistance(ohms) at all then the circuit is compromised? such as loose ground or actual wires broken or chewed and are touching.. maybe mice or something?

mtroxel

Just the opposite. I just tested mine for the heck of it. From the red wire terminal on the low beam plug to the ground post on the battery, I get 1.0 ohms with the headlight switch turned off. If you've got a short to ground, you'll get less than that...maybe .5 ohms or less?