Light Controller Exploded

[epipete]

If anyone is interested in the inside of their light controller then here are some pictures:

This one has had a previous repair, as can be seen here and the replaced ??? (whatever it is!)

Botched front.jpg

[RayD]

(whatever it is!)

Google'd

Ray

[Brit-Car-Nut]

High current, fast transistor. An electronic switch.

[epipete]

Ah, enlightenment!

[HJ2]

Haha.. Literaly!

[andy b]

Mine has just blown to over voltage of the alternator trying to get mine repaired mine has blown the same bit. andy b

[Enright]

Pete, what were the symptoms that led you to the module in the first place. Was one (or both) lights failing to come on or pop up?

[epipete]

Neil, iirc the problem that I had was that when I switched on the lights they lit but didn't rise, it was a bit intermittent as occasionally they would but, then again, sometimes they wouldn't. It was all rather erratic. I did find that by gigling the wires where they connected to the controller it would lift the pods.

[Enright]

Hmm, I consistently only had the left pod working.
I've just opened up my unit and the same part on the opposite side of the board has burnt out.

This lends a bit of weight to my theory that well lubricated pivots and linkages in the pod mechanism relieve stress on the motors, and also cut down on the current they pull, and therefore the stress put on the electronics that control them.

It certainly looks repairable, but where would I get the component from?

[epipete]

If you click Ray's link above it takes you to a data sheet for the component at the bottom of which is a link to a supplying company. I think that this might be a start point.

In fact check out eBay as they have several listed there

[GeoffSmith]

The BUZ10 is a long time obsolete and modern devices are a lot more robust.

If it's not urgent then I'll have a rummage in the loft or get you an IRFZ34 or two when I next order from Farnell and post them on to you.

[Brit-Car-Nut]

Geoff: Care to comment on the probable cause of the chip failure? Do you feel it caused by the motor drawing too much power trying to move the pod when the hinges and ball-joints are badly rusted or seized?

Controllers for our system are getting harder to find due to GM constantly improving the function - I know of at least 4 different and not interchangeable controllers used from 1985 to 1986, 1987 to 1992, 1993 to 1997 and then 1998 to 2002 model years where each version has different pinouts and different power levels to determine when the lamp housing is fully up or down.

Just thinking it might be time to narrow down the causes so owners can make repairs to prevent a very expensive part from failing.

[GeoffSmith]

Most likely a thermal issue as the fuses are 15A but it could be overvoltage due to inductive spikes.

Having looked into it a bit more Neil, I'd suggest using a AUIRFB3207 which is an automotive part, it is able to remain switched on until the cows come home (OK for 15A at 80°C ambient ignoring the board heatsinking effect) and has a 75V rating to help if it is an overvoltage issue. The only down side is that they are £1.50 each not £1.

[Enright]

Thanks for the input all.

I hadn't even considered eBay - good call Pete.

But the other reference number is even better Geoff. It's not urgent, but I'll probably give that one a go. it will be nice to have a spare module.
My only question is about the big hole in the transistor. I'm familiar with the 3 terminals, but what's with the big rivet through it - is it a heatsink or something?

John, I always thought that a bit of preventative maintenance went a long way. In the case of light pods I don't have a lot of evidence to back that up, but my Elan had done over 120,000 miles and I'm still on the original module and bushes.

[GeoffSmith]

I've had one to fix for years......

You are correct. The tab is for heatsinking and is usually also connected to the drain. The rivet is there because it's cheap and quick for production but a nut and bolt will suffice for hand crafted masterpieces.

[Brit-Car-Nut]

Neil: I agree maintenance is always the best way to minimize failures.

I can still find an occasional 1987 - 1992 Firebird/TransAM/Fiero controller at the local breaker yard. They usually sell for around $15.00 but USPS Postage is a whopping $25.00 for tracked shipping. I am willing to keep looking and let you know when one shows up.

I will have to put my car's headlamps back together to test any I find, but I probably need the practice and should try to find all of the pieces that I put safely away 7+ years ago.

[GeoffSmith]

Assuming your board is not quite as badly charred as the one I have, I'll send you the two new MOSFETs to try out at your leisure Neil:


Original thread

[Enright]

I'll take a pic and put it in my project thread later, but I don't think it's anywhere near that bad - thanks.