Windshield wiper Pump

[Army_Dude]

I traced it to the motor. I'm not getting any volage at the wires. Where do I go from here? Suggestions???

[Prerunner1982]

check the fuse, and see if you are getting power to the switch. When you tested the wires at motor, did you push the switch while you were testing? not to say you are stupid but sometimes we dont always think about what we are testing.

[Army_Dude]

Yep I had my boy hit it while I checked it. As for the fuse, I can't find one marked for the windshield washer. My switch is on the column. How can I get to it to test it? I traced the wires from the pump back to the block on the firewall. Gonna take a look at it tomorrow and see if I can get some sense out of it.

[Army_Dude]

Ok here's an update. I took the junction block off the firewall, I cleaned it with electrical connector cleaner. I put it all back together. Now I am getting 12.1 on the white wire. It drops to about 11.5 or so when I hit the switch. I have not bought a new pump motor yet. Don't want to waste the money if it's not going to work anyways. Ideas?

[beaterC10]

Did you check the ground connection? You should be able to jumper 12 volts and a ground directly to the motor and tell if that is the problem.

[Metallicamaro]

well have to tried to hook direct current to the pump to see if the pump works?

[us111]

hello,,not sure what year you are talking about but whatever year,if u have 11.5 v at the pump more than likely pump is bad,,,on my 76 the whole new replacement unit (wiper/washer) was $30.00 at autozone,,,but again,not sure what year we are talking about.... good luck

[Army_Dude]

Let me back up and give you guys a little more info. The washer system was FUBAR to start with. I replaced the hoses and took off the reservoir to check the motor. The motor was rusted into and came out in pieces. I went to the Zone and got a new one which did not work when I hooked it up. I returned it and instead changed my rear end dope. Meanwhile I tried troubleshooting the problem. I first got no voltage whatsoever at the plug for the motor, I traced them back to the junction block on the firewall. I took it off and cleaned it the best I could with electrical connector cleaner. I put it back on and now I am getting a constant 12 V on the white wire. Whether I check the white and the red or if I just check the white and ground out on the block. When I hit the washer switch, voltage drops a little but not much.

I may be screwed up here, but shouldn't voltage be present only when you hit the switch? I'm lost in the sauce.

Oh BTW it's an 85 model.

[85oldbluetruck]

I am fighting a similar problem but I suspect that the 2 pumps I have gotten at Autozone. I will try one from another place tomorrow.

[piecesparts]

Originally Posted by Army_Dude

Let me back up and give you guys a little more info. The washer system was FUBAR to start with. I replaced the hoses and took off the reservoir to check the motor. The motor was rusted into and came out in pieces. I went to the Zone and got a new one which did not work when I hooked it up. I returned it and instead changed my rear end dope. Meanwhile I tried troubleshooting the problem. I first got no voltage whatsoever at the plug for the motor, I traced them back to the junction block on the firewall. I took it off and cleaned it the best I could with electrical connector cleaner. I put it back on and now I am getting a constant 12 V on the white wire. Whether I check the white and the red or if I just check the white and ground out on the block. When I hit the washer switch, voltage drops a little but not much.

I may be screwed up here, but shouldn't voltage be present only when you hit the switch? I'm lost in the sauce.

Oh BTW it's an 85 model.

Army Dude is back--Hey Bro how's the war going. That truck still running, with the new motor?

[grinch4om]

ok army, stop and think...when ever you have a component that is inop, check fuse first, then go to the component and try to energize manually,apply voltage and ground and see if it works, if it does , problem is elsewhere. un plug devise and turn on whatever switch it uses. where line voltage present is power, other is ground. if voltage present, plug in component and apply ground to other wire, component should work if previous test of component is good. In DC voltage, a componant will "use" voltage so voltage reading after componant on ground side will be lower than on power side. absolutely different from AC power. simplistic explanation but after decades at dealers as their electric guy, this method is expedient and accurate. Of course a schematic is essential for any in depth problems...

[Zoomad75]

Which system are we dealing with? Is the pump the mechanical style on driven by the wiper motor or is it an electric pump at the washer bottle?

Having just converted mine from the old mechanical style to the electric pump I've got some detail on how the stock system works. Well at least the 73-80 setup. However I don't think the switches changed much unless you have the intermittant setup.

The stock system has power to the washer solonoid as long as the wiper motor is on. The way the washer pump is engauged is by completing the ground circuit for the pump solonoid when the button is pressed in. On mine, the yellow wire to the pump solonoid was the power and the blue was the ground back to the switch. I tried installing my electric pump and still couldn't get it to work when hooked up this way. I then grounded the pump manually with the wipers on and the pump worked. Turns out my switch wouldn't provide the ground when the washer was activated. I swapped in a spare switch I had and everything started working again.

You have checked for voltage to the pump, did you check to see if it was getting the ground signal from the switch??? Here's a Schematic for the 73-80 setup: