Is it the Multifunction Switch??

Hi,

I've been having this issue with my washer pump all summer. I've tried troubleshooting it myself after reading all the threads on this forum about the issue, but now I've come to a impass. I have a 2002 grand prix gtp. My washer pump would work sometimes and sometimes it won't. Even when it does it's just for a short time and the fluid coming out on my windshield the flow isn't so powerful like it used to when the car was new.

I have connected my washer pump straight to the battery and it's fine. I've checked the terminal that connects to the pump with both a multimeter and a test lamp and there is no voltage there consistently. Everyonce in a great while I would get voltage there and hence probably why the pump works everyonce in a while. I've traced the wire (red in color) all the way back to the fuse box under the hood. With a test lamp, there's no voltage there either when the washer pump is activated at the multifunction switch. Strangely enough, I think my fog lights went out at the same time as my pump. Although, I had replaced my stock fog lights with a Blazertech, could the two be connected? For whatever reason, my fog lights came on last night, but not today. I have also noticed this that whenever I start the engine, I can activate the washer pump almost every time for 1-2 seconds and thereafter the pump won't work unless I shut off the engine and restart it. Of course, this doesn't help when driving in snowing and dirty road conditions. Lastyly, the LED clock screen on the radio sometimes does not light up. The radio works and I can see that the display is still working as I change the station I can see the numbers changing. That happened today as I started up my car. Now later in the day the display is illuminating normally again.

My question is...could there be a problem in the junction block or is it the multifunction switch itself?? Besides purchasing a multifunciton switch, is there a way to check it? Or do I have a general electrical problem that is giving me general problems?Thanks. Any help would be greatly appreciated.

50/50. IMO either the multifunction switch or the ignition switch.

Do you have the GM wiring diagram? It would help.

I did a few more testing and found the following. Grounding from C2 location F12 of the junction box in the underhood fuse box is good. Continuity testing from the same location to the connection point where it connects to the washer pump is also good. My knowledge of electrical diagram is limited. I couldn't tell if according to the wiper and washer electrical diagram (link below) if the wipers are still good if the "mist fucntion" is not working. In another word, when I activated the "mist" function my wipers will still come on, but I just don't have the washer pump working. With this system, can the multifunction still be a possible cause?

Thanks.

http://files.automotiveforums.com/gallery/uploads/420758/Wiper_and_Washer.gif

http://files.automotiveforums.com/gallery/uploads/420758/Fuse_Box_Underhood.gif

http://files.automotiveforums.com/gallery/uploads/420758/Column_Ignition.gif

I finished troubleshooting my washer pump problem today and the problem turned out to be my cruise control lever. I discovered that if I twist the lever hard when trying to activate the "mist" function the washer pump comes on every time.

I was thinking of taking the cruise control lever apart to see if I can clean it. If not, I may purchase a new one from Napa or Autozone. They appear to carry some levers from Dorman for reasonable prices. The only thing that concern me is that the levers that they carry seems to be for older models ( up to 1996). I have a 2002. Would it matter. If anyone has taken apart the cruise control lever, I'd greatly appreciate if you can give some suggestions.

Thanks

Autozone should have the aftermarket Duralast brand multifunction switch for your year GP. Cost at over $350 though. Part number - SW2146. Or try a used one from a salvage yard or Ed Morad Parts Company on Ebay. If you decide to take it apart good luck.