wipers work but no washer fluid

[hummer4x4guy]

Can anyone help figure out the proper way to see what is the reason I have low and high wipers but when I push to wash I get no fluid and the resevior is full.
Thanks.

 

[porkysplace]

Is there power to the pump ? If so probably a bad pump.

 

[hummer4x4guy]

Pump is only a few years old. Installed new. I'll take off the two wire leads going to the pump and see if I have power going to it.

 

[hummer4x4guy]

When I test the two wire ends for the pump on continuity I get "004" on the multimeter. When the truck is running and I push in for the pump the numbers vary around but never get over 24v.

 

[MtnSnow]

Sounds like you have a bad switch then if you are not receiving voltage at the pump when pushing the switch. Also have you tried to operate the washer pump using jumper wires directly to power/batteries to confirm that the pump is capable of working?

 

[hummer4x4guy]

I haven't tried hooking it right to the batteries yet., so I'll do that. I did try a spare switch and it seems like I was getting the same wacky voltage reading.

 

[Retiredwarhorses]

If the wipers work you are getting 24 to the motor, there are 3 connectors in the A-pillar P W G, Park,washer, ground.
washer is wire 71, 27 park, 57 grnd
personally, replace the squirter motor...of you can't hear it go on and off, it's 95% chance it's bad.
no uncommon, they get gunked up I find.

 

[hummer4x4guy]

I got around to working on the pump today and hooked it up to the batteries and it just sparked once I touched the final wire. I assume this means the pump simply has a short? When I tested the voltage at the batteries tho it was showing 32-34V!! So Ill have to also check the voltage regulator and see if thats set too high. But last time I set it I was right at 26.4ish. Ill assume the voltage fried the pump.

 

[Retiredwarhorses]

No...pump failure is quite common. I see it all the time. While over voltage is bad, you are overcharging your batteries.
thus, you are cooking them and they will fail, or better yet...explode....ask me how I know this...LOL


i have a customer truck in right now that blew the caps off the front 6TL...he is lucky it didn't cause more damage then it did.

 

[hummer4x4guy]

****!!! I believe it. I'm going to order a new regulator as soon as my best offer time runs out. Unless you have one?

 

[Retiredwarhorses]

Frankly, I don't bother, I just replace the generator, there are tons of 60amp gens out there due to all the m939 trucks being scrapped...I picked up a few for shop spares for 100.00 ea.
now and again I see NOS for 250.00

 

[hummer4x4guy]

Oh I haven't seen take out ones around. I'd consider that route since getting the back off and on sorta sucks.

 

[hummer4x4guy]

OK I got the new pump in and its working. But what should my voltage be showing at the alternator?

 

[jeremymx26]

Voltage should be adjusted to 28volts +-0.5

 

[hummer4x4guy]

That's what I thought. I could go as low as 30volts but at that setting the trucks volt meter was in the yellow. So I turned it up till it was online with the hash mark in the green. Once t that point the wiper pump started to work. Something must be messed up still I fear.

 

[jeremymx26]

Maybe try another voltmeter just to be sure.

 

[hummer4x4guy]

I was also measuring the volts off the alt with a multimeter device. Maybe that meter is junk?

 

[Retiredwarhorses]

So once you turned it up to meet the mark, what was its output ?
28.5 is max. Your gauge is possibly flaky, or your meter...cuz the metered output don't lie....regardless of what's on the gauge.

 

[hummer4x4guy]

28.5 is the max setting of the regulator or that's the safest max output it should be set? 33 volts is the lowest I was able to achieve at the alt wires.

 

[Retiredwarhorses]

If your lowest you could get is 33 volts, your regulator is shot. You will cook the batteries at that voltage.
i have a truck in the shop,right now that blew a battery...yes, it blew up. Was running at 33volts...blew the caps off when he started the truck...