Intermittent wipers not working, is there a control box?

[Old65C10]

So, I am working on my 90 Suburban V2500. When I got the truck the Cruise did not work and I replaced the turn signal stalk. I hoped that this would fix the int. wipers also, but I found out the switch for the wipers is farther down in the column.
So, the wipers work on low and high, but not intermittent. This makes me think the switch is OK, but that there is a control module somewhere. Is that true? If so, where is it located?
I am trying to track down the last few little gremlins, I am down to this and the horn.
Any help would be greatly appreciated.

[hatzie]

The module is on the column behind the small sheet metal panel in the knee bar.

You may be able to change the electrolytic capacitors in the module and bring it back to life. Use good quality Rubycon or Nichicon capacitors rated for as many hours as you can get not Chinese floor sweepings.
You'll need to put more paste on the transistors where they contact the aluminum heatsink.

[SunSoaked]

I bought it new off RockAuto, AC Delco branded and the POS did the same thing as yours. I unplugged and removed it and will worry about it later.
Frustrating to spend $80 bucks on something and not have it work. Like Hatzie said, Chinese junk.

[hatzie]

I don't trust Doormat and Broke When Delivered. AC Delco is now China Delco so I don't trust them either. Even the parts from GM dealerships are the same Chinese crap now for eight times the price. Sad state of affairs.

If the Delco part was a US made part that's been on the shelf for a decade or more it could go bad on the shelf. Electrolytic and tanatlum capacitors have a useful lifespan of about a decade or a little more. Not all of them will fail but the old units don't meet the capacitance spec in farads and usually have much higher ESR (Equivalent Series Resistance). I test the ESR and capacitance of all caps that I install just in case I got some old parts.
Panasonic (Japan/Korea), Nichicon, and Rubycon capacitors are rated in thousands of hours runtime. Pick the caps with the longest runtime ratings. We're talking $0.10 or maybe $0.15 difference in price for the longer life parts a lot of the time. The el-cheepo Chi Com discrete components are not enough cheaper to make their significantly lower lifespan and dodgy adherence to spec worthwhile.

I've repaired the 78-83 modules. It's a single sided board. Usually the DIP chips are just fine... ancient electrolytic capacitors or worst case bad diodes or carbon resistors.
I've never pulled one of the 85-91 units apart but I've seen and repaired the guts on the Fiero and ST truck modules. Several electrolytic capacitors on those boards.
Here's a thread from Pinnocks Fiero board on rebuilding the Fiero Pulse Wiper modules that are very similar to the units GM used on our trucks between 1985 & 1991.
http://www.fiero.nl/forum/Archives/A...-2-055146.html

If you don't have the tooling to recap them farm it out. It'd be a pisser to lift traces by overheating the board with a WalMart soldering iron while you're desoldering components.

[Old65C10]

Thank you for all of that info. Not exactly what I wanted to hear, but the truth is China stuff is a real gamble these days and I would rather fix it right then spend a bunch of money and have it fail in a few months.
I will see if I can find it and pull it apart.

[1774btcrew]

Originally Posted by hatzie

I don't trust Doormat and Broke When Delivered. AC Delco is now China Delco so I don't trust them either. Even the parts from GM dealerships are the same Chinese crap now for eight times the price. Sad state of affairs.

If the Delco part was a US made part that's been on the shelf for a decade or more it could go bad on the shelf. Electrolytic and tanatlum capacitors have a useful lifespan of about a decade or a little more. Not all of them will fail but the old units don't meet the capacitance spec in farads and usually have much higher ESR (Equivalent Series Resistance). I test the ESR and capacitance of all caps that I install just in case I got some old parts.
Panasonic (Japan/Korea), Nichicon, and Rubycon capacitors are rated in thousands of hours runtime. Pick the caps with the longest runtime ratings. We're talking $0.10 or maybe $0.15 difference in price for the longer life parts a lot of the time. The el-cheepo Chi Com discrete components are not enough cheaper to make their significantly lower lifespan and dodgy adherence to spec worthwhile.

I've repaired the 78-83 modules. It's a single sided board. Usually the DIP chips are just fine... ancient electrolytic capacitors or worst case bad diodes or carbon resistors.
I've never pulled one of the 85-91 units apart but I've seen and repaired the guts on the Fiero and ST truck modules. Several electrolytic capacitors on those boards.
Here's a thread from Pinnocks Fiero board on rebuilding the Fiero Pulse Wiper modules that are very similar to the units GM used on our trucks between 1985 & 1991.
http://www.fiero.nl/forum/Archives/A...-2-055146.html

If you don't have the tooling to recap them farm it out. It'd be a pisser to lift traces by overheating the board with a WalMart soldering iron while you're desoldering components.

Who would you suggest to send these out to for repair? I have a frew of the 78-83 ones

[hatzie]

I have the equipment and experience to replace the dead electrolytic capacitors and any diodes and resistors that don't meet spec.
I do not have a truck to test it in anymore.

The 78-82 GM units I've opened up used six-ish electrolytic capacitors, at least one glass Zener diode, several 1/4 watt power diodes, a handful of 1/4W resistors, at least two TO92 transitors, and one TO220 package device probably a FET.
The DIP chip is a CD4001 CMOS Quad NOR Gate. The old CMOS TTL chips are easily available as are quite a few flavors of TO92 package transistors and TO220 package FETs.

Unfortunately I didn't draw up a schematic of any of the 78-82 boards I rebuilt. If I ever lay my hands on another I intend to do just that. I've never done an 85-91 module but they shouldn't be much different from the Fiero & ST pulse boards.

Usually it's just ancient electrolytic capacitors that dried out and turned into resistors.