What Component Exploded in the Wiper Delay Module of a 1985 Chevy C10?

[vfeinman]

[URL]http://files.victorfeinman.com/files/Photos/IMG_6506.JPG[/URL]

What is the black and grey thing that blew up? I need to replace it. It comes from the wiper delay control module from my 1985 Chevy C10 Silverado.

Thanks,
Victor

 

[NascentOxygen]

It looks like a diode or zener diode. Possibly similar to the one to its top right. But there is no point replacing it just yet. It blew up because some other fault caused far too much current to flow through it. If you replace it, there's every likelihood that you'll just see it self-destruct immediately you connect 12 v. You need to fix the fault, before replacing what it damaged. First, check for short-circuited tracks on the card, or the leads of something causing an unplanned short.

See whether you can read a number off it, compare this with the numbers on other diodes on the card.

 

[vfeinman]

Thank you so much for your reply, I wasn't sure if it was a capacitor or a diode. Could you tell me specs on it?

As for the reason why it shorted - it's 26 years old, could the age do it? And the truck looks like there has been work to it in the past, could it have been shorted outside the card? I mean it wouldn't be costly at all for me to replace it just to see it pop again, I'm willing to take that risk. A new wiper delay control module is $70-100 and that's not even guaranteeing it will work.

Below is the flip side of the card, do you see any potential shorts / problems?

[URL]http://files.victorfeinman.com/files/Photos/IMG_6508%5B1%5D.JPG[/URL]

Thank you so much!

-Victor

 

[AlephZero]

It appears to have 3 leads (on the right hand side) so it is unlikely to be any sort of diode.

I would guess it is some sort of transistor, but without the part number, or drawing the complete circuit diagram and then figuring out what its function is, there's no way to guess what to replace it with.

 

[NascentOxygen]

It appears to have 3 leads (on the right hand side) so it is unlikely to be any sort of diode.

No. We are talking about the charred diode near the light blue capacitor.

The resistor alongside it is charred, too, suggesting the fault caused it to cook. Other components may have been destroyed, just not so spectacularly.

 

[DaveC426913]

Other components may have been destroyed, just not so spectacularly.

Yep. Including causing that one in the lower left to spontaneously convert itself to marshmallow.

 

[NascentOxygen]

It's difficult to make much of photos, but I can see that one end of the dead diode goes to one of the pair of galvanized edge connectors, so maybe it got too high a voltage on that lead from off the card. But have a better look at that pair of adjacent galvanized edge connectors--it looks like a clipped lead may be close to shorting from the adjacent terminal to the one that feeds the diode.

I think you are going to have to buy a new card, or else hand it in at an electronics repair shop. The fact that it was destroyed so spectacularly suggests it isn't just one component gone bad.

 

[NascentOxygen]

Yep. Including causing that one in the lower left to spontaneously convert itself to marshmallow.

I called that paint. There's some on the electrolytic adjacent.

 

[vfeinman]

Yep. Including causing that one in the lower left to spontaneously convert itself to marshmallow.

LOL

Thanks for the laugh DaveC426913!

Umm shoot, so if I get this straight, there are probably more problems and busted components than just the diode, and I'm probably better off ripping one off a junker in some junk yard somewhere?!

Thanks everyone for their input.
-Victor

 

[AlephZero]

I called that paint.

I'll buy the idea that the "marshmallow" is actually covered with thermal grease, if you removed a heatsink to take the pictures.

Yup, the other component looks like a diode.