1996 Blazer - No voltage at front washer pump

[mixin]

Going into winter, I thought it best to start looking into why my front washer pump is not working. I checked for voltage at the pump with my multimeter several times to make sure I had a good connections and good ground. There was no voltage on either wire when operating the washer switch. The wipers work fine.

Can someone give me some advice to start t-shooting here? I'd like to be able to find out where the voltage stops before I start throwing parts at it. Thanks!

Mike

[mcmalloy]

not sure but i think the power for the washer pump comes from the wiper motor, you can slice into the wire for the pump and give 12 volt power to see if it works,

[old_master]

If the wipers work, the fuse is good, they use the same fuse. The dark green wire runs from the wiper switch to the washer motor. The black wire at the washer motor connector must show less than 5 ohms resistance to ground at all times. The dark green wire should show battery voltage at the washer motor when the washer switch is activated.

[mixin]

Originally Posted by old_master

If the wipers work, the fuse is good, they use the same fuse. The dark green wire runs from the wiper switch to the washer motor. The black wire at the washer motor connector must show less than 5 ohms resistance to ground at all times. The dark green wire should show battery voltage at the washer motor when the washer switch is activated.

Thanks OM, Using the ground in the washer pump harness and chasis ground yielded no voltage. I'm assuming you want me to check for voltage coming out of the multi-function switch? Is there a good spot to find the dark green you speak of to see if 12v is coming from the switch?

[old_master]

The only way to access the dark green wire at the multifunction switch is to remove the column covers and the bolster below the column. If there is no voltage on it when you activate the washers, you might look on the main Blazer page: in the How-to section there is a thread about cleaning the contacts inside the switch. Might help, might not, but it's worth a try, the multifunction switch is expensive. If you have voltage on the dark green wire, then there's an open circuit, (broken wire) somewhere between the switch and the pump motor.

[mixin]

Originally Posted by old_master

The only way to access the dark green wire at the multifunction switch is to remove the column covers and the bolster below the column. If there is no voltage on it when you activate the washers, you might look on the main Blazer page: in the How-to section there is a thread about cleaning the contacts inside the switch. Might help, might not, but it's worth a try, the multifunction switch is expensive. If you have voltage on the dark green wire, then there's an open circuit, (broken wire) somewhere between the switch and the pump motor.

I'll try it tomorrow when I have a little more light. If it is the multifunction switch, I don't know if I can justify the expense (wow, you were right - very expensive). I think I would just install a normally open momentary switch in one of the blank panels of my headlight switch area and use a relay to throw 12v to the pump directly. We'll see, I'll let you know how it turns out. Thanks again.

[mixin]

Ok, finally had a minute to get at it. I pulled the lower shround off the steering column to expose the harness coming out of multifunction switch (MFS). With the washer pump motor unplugged, I checked for voltage on the only dk green coming out of the switch while operating the washer - no voltage. I checked for continuity between this dk green coming out of the switch and the dark green at the pump - no continuity. The dk green coming out of the MFS showed continuity to ground whether I was operating the washer or not.

On ebay, I found an aftermarket MFS for ~$60 and a Delco one for ~$108. If you think I've properly diagnosed the problem as a bad MFS, I may be inclined to replace it - is aftermarket ok? OR I may still install my own switch with a relay - i'm on the fence.

Please let me know if I've done the t-shooting correctly. Thanks!!

Mike

[old_master]

Mike,
My mistake, I originally looked at the rear washer motor wiring, sorry. The front washer gets its power from fuse #17 (25 amp) in the instrument panel fuse box. From the fuse to the multifunction switch it is a yellow wire and should show battery voltage in the run and accessory position. When it leaves the multifunction switch it changes to a red wire and runs to the front washer pump. At the pump electrical connector there is also a black wire. The black wire goes to body ground and should show less than 5 ohms resistance at all times. The red wire at the pump connector should show battery voltage when you activate the washer switch with the ignition in run and accessory position. Sorry for my screw up. Let me know what you find with the correct information

[mixin]

I do not have a red wire coming out of the MFS.

At the front washer pump, I have a dark green wire and a black wire.

Sorry to add more trouble here, thanks for your continued help.

Mike

[mixin]

So I took the cheap route and wired up a new switch and relay. I spent some extra time and did a sweet job with a small momentary push button switch mounted to the signal stalk. So when I pushed the button, I heard the motor spin but no blue juice. SO, I figured I needed to get a better look at it and I pulled the airbox (you can see where this is going). WOW, ANOTHER PUMP!!! The pump I wired up (and had been testing the whole time) was the rear washer pump!

@#$%#$^%@!!!!! and @#$%#$^@#$%!!! *throw tools*

Of course the correct front pump had voltage at the pump when I turned the stalk forward to wash...10 minutes, new pump, fixed.

SO, since I have this sweet momentary switch mounted to my signal stalk with a relay and everything, I figure it's AIR HORN TIME!!! hahahaha!

Mike

[old_master]

OOps! Glad you got her working. With this snow storm that just went through, you really need the washer working! I'll be in GR tomorrow, better fill up my washer tank!