Headlight problems... combination switch or something else?

RowanT · Post by **RowanT** » Sun Mar 23, 2014 1:21 pm

We have a 1990 L300, we've been having headlight problems (described below). From searching previous posts, I think it could be an issue with the combination switch, but I wanted to see if anyone had any other suggestions or thoughts before I start pulling things apart as Falco described.

The problem has changed/developed over the last month or so. Initially the right headlight just started getting a bit dim. Then both headlights started getting "stuck" on so that the only way to turn them off was to pull a fuse (6th from the left on the top row in the fuse panel under the dash on the driver's side). Initially this only happened after going to high beam, but now it happens whenever the lights are switched on. The left headlight which was dim to start with has now gone out entirely, the high beam light on the dash is always on, and high-beams have stopped working entirely. The running/parking lights also no-longer work.

The other thing that might be worth mentioning is that when I pull the fuse to switch off the headlights, I can hear a relay trip, and it sounds like its in the daytime running light unit. The one remaining working headlight actually still works with the fuse removed, so we've just started leaving it out...

Does this sound like a combination switch problem, or is something else likely to be going on? I also wondered whether it could be an issue with the daytime running light unit (a TruckLite DRL).

Any advice or suggestions would be greatly appreciated!

Thanks!

Rowan.

Post by **FalcoColumbarius** » Sun Mar 23, 2014 2:33 pm

Hmmmm..... Do you have an air compressor with a Japanese air blower? With my experience (which is limited) the main issue that led to the combo switch event of a life time was dust. This led to the contacts sticking, then arcing. Consequently breaking off the switch toggle.

Another thing you might look into is the DRL unit, itself.

Also consider the fusible links in the battery bay.

I see you live on the Shore. As it happens, so do I. If you like we could meet. I've sent you a PM.

Falco.

Firesong · Post by **Firesong** » Sun Mar 23, 2014 2:57 pm

Switch possibly. Similar but not quite to a flaky alternator.

RowanT · Post by **RowanT** » Mon Mar 24, 2014 2:34 pm

Thanks for the quick suggestions. Falco - I'm not sure, regarding the air compressor. Is there an easy way to tell?

Dust could definitely be a factor, as I did a couple of very dusty trips over the Hurley FSR and around the Chilcotin over the summer. I'll see if I can figure out how to disconnect the DRL this afternoon and poke around to for any signs of melted wires in the battery box this evening.

Firesong · Post by **Firesong** » Tue Mar 25, 2014 7:38 am

Oh yah. Those stupid drl modules are horrible too! Good call.

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