Wipers on 99 Silverado 4by4 1500 suddenly only works at full speed. Fuse under dash okay. Manual mentions circuit breaker but don't know. Problem happened as turned on wiper to move heavy very, heavy snow.Checked under hood even though have no windshield wiper connect and pushed all fuses to make believe I know what I'm doing. Any help?

There was a recall a while back ago for this problem. Check with your local dealer and see if the recall is still active. The problem is the circuit board on the wiper motor assemble where the wire harness connects. The solder the plastic clip on the board breaks and will cause this problem and at worst the wipers don't work at all. If you good with soldering, it's a simple fix by just re-soldering the wire harness clip back on and if you like you can buy the replacement circuit board at Auto Zone. The will have the step by step instructions for you to get the job done, a light tap will once and a while fix the problem but you may loose the whole function of the wipers. Good luck.

Hi,

I just had the exact same problem and fixed it myself without buying any parts. I removed the Wiper Pulse Module (also called the wiper motor cover because that's also what it does.) Under the plastic vented air dam is the Wiper Motor. Three screws on the top of the motor plastic cap allow you to remove it, then unplug it from the wiring harness. Do it in this order to reveal the plug catches without breaking them. Then, flip over the cap to reveal a printed circuit board. With a small screwdriver, remove the circuit board from the plastic cap and inspect. Look carefully at one of the large resistors (Black with silver stripe) mine was snapped in two. Also, inspect both sides of the board for burned circuit paths on the surface (there was one very small disconnect path on the back of the board.)

Remove the broken resistor and replace (I believe that it is a zero ohm type resistor) or, you may solder to two pieces back together and cover with some shrink tube. Reinstall the resistor. If you have any disconnected circuit paths on the board, you may solder a small wire jumper across the break to complete the circuit. Reassemble the board with the plastic cap and reinstall the cap onto the motor and plug it in. I recommend testing the setup before reinstalling the wiper arms and air vent. You will be able to here whether it works or not. The whole thing took about two hours to find and fix. The retail price of a circuit board is $130.00, the cheapest is about $84.00.

This is not too terribly difficult if you can use a solder gun and will save you some bucks.