98 Blazer 4x4 LS

Front windshield washer pump sprays fluid. No spray any more nor any pump noise when pressing rear washer sprayer button. Is it the same pump , front & rear?

If the same pump, is there a diagnosis procedure to find the issue? Any common problems? i.e.
Electric button fails, wiring plug corrosion, etc?


If different pump then where is the rear pump located?

Thanks.

 

On my 2000 there are 2 pumps. One at the bottom of the reservoir for the windshield and one above it for the rear window. Yours should be the same. Start simple with the fuse and move on to a test light or voltmeter at the plug. If your pumps are the same you could switch them and see if one has failed.

 

Not really sure.But if how`s the fluid level?I thought the same thing one time.I put the windshield wiper washers on one morning, neither front or back where working.Come to find out..the fluid level was low.If you do have a rear pump?It would be located in the lift gate area or the tail gate area it self.

 

If it was just low on fluid he would still hear the pump

 

I think the electrical connectors are the same between the two pumps so you can switch them to rule out wiring and such. Or just apply fused 12V across the pump terminals to see if it works.

 

Is there a separate fuse for each of the pumps?

 

If you don't know for sure, research before posting so you can make an educated post or DO NOT POST! It's quite simple really.
It is located in the washer reservoir about 6" above the front pump. Again, if you don't know either find out for sure or don't post.

WalkGood,
Since the rear pump is located higher in the tank than the front pump, it is possible for the fluid level to be below that of the pickup for the rear pump, causing it to run dry. You should still be able to hear it although it may not make as much noise when running dry than when flooded.

If you still cannot hear the pump, then it is possible that the pump is either bad, wiring damaged, the fuse is blown, or the washer switch in the rear wiper/washer control switch is bad.

The schematics that I have (from my 2000 FSM) show that the rear wiper motor controls and the rear pump both get their power from the same fuse so suffice to say that if the rear wiper works, the fuse is good and you can move to other things. If you wanted to check out the fuses, RR WPR fuse (15A - #23 in the IP fuse box) and RR W/W (15A - Under hood fuse box) both are used in the operation of the rear wiper & washer system. The RR W/W fuse only powers the wiper motor itself.

You can test the switch by removing the switch panel from the dash, disconnect the wiring connector, and testing for continuity between pins A & B at the back of the switch assembly with the washer button pushed. If that tests out ok, then you can move to under the hood for further testing. While the connector is disconnected, you can test for +12V at terminal A in the connector (key 'on'). This will also confirm that the RR WPR fuse (#23 in the IP fuse block) is good.

Once you have pulled the air filter housing from the truck, you will have one bolt that holds the washer reservoir into the truck (there likely are youtube videos on doing this). The lower part of the reservoir is just held in place by rubber grommets. With the reservoir out, you will see the two pumps. The one for the front is at the bottom of the reservoir and the upper one is for the rear. You can test for voltage at the connector for the rear pump while someone presses the rear washer button with the key in the 'run' position. If you have +12V and a good ground at the pump and the pump still does not run, then the pump is bad.

Hope this helps and let us know if you have any further questions.

 

Thank you for the very detailed response much appreciated. Once I got the hood open and took a look I could see that the rear pump is higher. I was able to use a test meter to see that voltage is being sent to the pump when the button is being pushed but the pump doesn't work. Additionally I was able to supply direct battery voltage 12 volts to the pump itself and no joy. So I'm ordering a new pump and when it comes in from Amazon I'll be putting it in.

Thanks again for your response and everybody else who supplied useful information.

 

Glad to help!

 

For the pump motor to work, you need voltage AND ground, (there are two wires in the connector). The ground wire must show less than 5 ohms resistance to ground at all times.