Windshield washer problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jd21476 · 07-04-2014, 04:24 PM

My windshield washer motor has been inop for a while and I finally got around to looking at it. I ran 12v to the pump and nothing so I swapped the motor. With a new one but it still does not work. I ran 12v to the washer pump again and this one still did not work. Any ideas?

lilspike · 07-04-2014, 05:37 PM

Check the ground. My first guess.
Matthew

tucsonjwt · 07-04-2014, 06:05 PM

I would disconnect the harness connector to the washer pump and have an assistant operate the washer switch while you use a 12V continuity tester at the contacts in the connector. As I recall, you 73 washer pump is a separate unit, not integral to the wiper motor like later models, but I am not sure if it still uses the same 12V power source as the wiper motor. Since you can't operate the washer pump without turning the wipers on (I think), then it makes sense that they use the same power source.

It is possible that your 41 year old connector and harness need replacing. Sometimes the contacts or the connector housing itself become loose and make only intermittent contact.

Also, stating the obvious, make sure that your "squirters" at the cowl and the attached hoses are clear. A needle is good for cleaning out the squirters. Also, make sure that the line to the reservoir is without splits and holes and that the reservoir itself is in good shape, including the cap, and full of fluid.

jd21476 · 07-04-2014, 10:57 PM

Quote:

Originally Posted by tucsonjwt

I would disconnect the harness connector to the washer pump and have an assistant operate the washer switch while you use a 12V continuity tester at the contacts in the connector. As I recall, you 73 washer pump is a separate unit, not integral to the wiper motor like later models, but I am not sure if it still uses the same 12V power source as the wiper motor. Since you can't operate the washer pump without turning the wipers on (I think), then it makes sense that they use the same power source.

It is possible that your 41 year old connector and harness need replacing. Sometimes the contacts or the connector housing itself become loose and make only intermittent contact.

Also, stating the obvious, make sure that your "squirters" at the cowl and the attached hoses are clear. A needle is good for cleaning out the squirters. Also, make sure that the line to the reservoir is without splits and holes and that the reservoir itself is in good shape, including the cap, and full of fluid.

I checked the lines and they are all clear. I turned on the wipers and then ran 12v direct to the washer motor and it didn't work. This makes no sense to me.

jd21476 · 07-04-2014, 11:17 PM

So I just tried it again with a different battery and this time the pump worked. I then got in with a test light and I have power coming to the connector from the split off of the wipers but no power from the wire from the firewall. I'm assuming this wire is from the switch. Is that correct?

tucsonjwt · 07-05-2014, 07:42 AM

Jumping the switch wire will tell you if you have a bad switch.

donut · 07-05-2014, 08:51 AM

Check the switch, like tucsonjwt mentioned.
Is this a full on resto or just getting a good truck to enjoy?

My '73 went through 3 pumps in 4 mos. (luckily they had a warrantee.) Finally I gave up and wired in an aftermarket 12v inline pump. Further investigation said a later model washer tank with a 12v pump enclosed is a popular alternative. (maybe S-10 washer?)

IIRC, (and I may be wrong.) The pump is actually mechanical, with the power allowing it to engage.

jd21476 · 07-05-2014, 10:43 AM

Its just to have a good truck.

How do I jump the switch?

tucsonjwt · 07-05-2014, 12:50 PM

I have not seen a 73 switch since I sold mine 15 years ago, but I think the switch is screwed to the metal dash. The proper switch removal would be to remove the dash bezel, unscrew the two mounting screws for the switch, pull the switch out from behind the dash and let it dangle down. There should be a wire going in and out of the switch.

Step one is to use a 12V continuity tester to check for power at the switch (alligator clip hooked to metal dash, probe end stuck in the wire to the switch - try both wires, one should have power with the switch off, the other wire should have power with the switch activated.) If there is no power in the outgoing (load) side of the switch, then you need a new switch. You can jump the switch by joining the two wires (ingoing and outgoing) together to see of the pump operates

I can't remember if there is a separate switch for the pump, or if it is integral to the wiper switch. There may be two outgoing wires, one for the pump and one for the wiper motor, so you might have to jump both alternately to see which one is the pump power.

You may be able to remove the connector at the back of the switch and just
jump the contacts to get the pump to work - same deal - attach the alligator clip to one contact and probe the other contacts. Make sure you use firm pressure on the probe and that the clip is hooked on there firmly.
Be careful where you are poking that thing so you don't arc out something and blow a fuse. I am not sure if the switch gets its ground from being screwed to the metal dash - if so, then jumping the connector contacts probably won't work.

jd21476 · 07-05-2014, 01:34 PM

Ok, Ill try that. Thank you

tucsonjwt · 07-06-2014, 03:25 PM

If you go the the AutoZone website you should be able to search for a wiring diagram for your truck. You will have to sign up and log in, and maybe search for your year, make, model of washer pump first.

It looks like there are multiple wires to/from the switch to the pump, but they do identify which one is ground so that should help. Unfortunately, they do not indicate which wires are for which function. My wire colors don't match the wiring diagram, so I don't know if the color scheme will help you much.

jd21476 · 07-06-2014, 04:19 PM

So I did some troubleshooting on the switch and I think the switch is bad. I ordered a new one but the weird thing is that the switch is from a 1975 model and my truck is a 1973.

tucsonjwt · 07-06-2014, 04:35 PM

Did you check the LMC website?

http://www.lmctruck.com/icatalog/cc/full.aspx?Page=183

willett · 07-06-2014, 10:50 PM

There is constant hot to the pump, ground is switch controlled.

KrazyRay · 07-07-2014, 03:16 PM

There's a mod somewhere on this forum using a 85 an newer washer bottle that has the pump in the bottle. Its supposed to be much more reliable.

tucsonjwt · 07-07-2014, 04:20 PM

Since I went with a Delco wiper motor/washer stock setup I have not had any problems in the past 12 years. I previously had bad luck with aftermarket motor/pump units. This is for my 83, so you have to get a motor with the pump as one unit. I think the earlier squares used a detachable pump. But the Delco is $98 vs. $50 for the aftermarket.

07-04-2014, 04:24 PM	#1
jd21476 Registered User Join Date: Aug 2013 Location: San Diego, CA Posts: 236	Windshield washer problem My windshield washer motor has been inop for a while and I finally got around to looking at it. I ran 12v to the pump and nothing so I swapped the motor. With a new one but it still does not work. I ran 12v to the washer pump again and this one still did not work. Any ideas? __________________ 1973 Chevy K20

07-04-2014, 05:37 PM	#2
lilspike Registered User Join Date: Apr 2012 Location: Shady Valley, TN Posts: 25	Re: Windshield washer problem Check the ground. My first guess. Matthew

07-04-2014, 06:05 PM	#3
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,189	Re: Windshield washer problem I would disconnect the harness connector to the washer pump and have an assistant operate the washer switch while you use a 12V continuity tester at the contacts in the connector. As I recall, you 73 washer pump is a separate unit, not integral to the wiper motor like later models, but I am not sure if it still uses the same 12V power source as the wiper motor. Since you can't operate the washer pump without turning the wipers on (I think), then it makes sense that they use the same power source. It is possible that your 41 year old connector and harness need replacing. Sometimes the contacts or the connector housing itself become loose and make only intermittent contact. Also, stating the obvious, make sure that your "squirters" at the cowl and the attached hoses are clear. A needle is good for cleaning out the squirters. Also, make sure that the line to the reservoir is without splits and holes and that the reservoir itself is in good shape, including the cap, and full of fluid.

07-04-2014, 11:17 PM	#5
jd21476 Registered User Join Date: Aug 2013 Location: San Diego, CA Posts: 236	Re: Windshield washer problem So I just tried it again with a different battery and this time the pump worked. I then got in with a test light and I have power coming to the connector from the split off of the wipers but no power from the wire from the firewall. I'm assuming this wire is from the switch. Is that correct? __________________ 1973 Chevy K20

07-05-2014, 07:42 AM	#6
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,189	Re: Windshield washer problem Jumping the switch wire will tell you if you have a bad switch.

07-05-2014, 08:51 AM	#7
donut Registered User Join Date: Aug 2009 Location: S.C. Posts: 1,593	Re: Windshield washer problem Check the switch, like tucsonjwt mentioned. Is this a full on resto or just getting a good truck to enjoy? My '73 went through 3 pumps in 4 mos. (luckily they had a warrantee.) Finally I gave up and wired in an aftermarket 12v inline pump. Further investigation said a later model washer tank with a 12v pump enclosed is a popular alternative. (maybe S-10 washer?) IIRC, (and I may be wrong.) The pump is actually mechanical, with the power allowing it to engage. __________________ '86 C-30 dually, 454/tbh400 '73 K-20 350/350/205 (sold ) I'm kinda like duct tape- no real purpose, but handy to have around.

07-05-2014, 10:43 AM	#8
jd21476 Registered User Join Date: Aug 2013 Location: San Diego, CA Posts: 236	Re: Windshield washer problem Its just to have a good truck. How do I jump the switch? __________________ 1973 Chevy K20

07-05-2014, 12:50 PM	#9
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,189	Re: Windshield washer problem I have not seen a 73 switch since I sold mine 15 years ago, but I think the switch is screwed to the metal dash. The proper switch removal would be to remove the dash bezel, unscrew the two mounting screws for the switch, pull the switch out from behind the dash and let it dangle down. There should be a wire going in and out of the switch. Step one is to use a 12V continuity tester to check for power at the switch (alligator clip hooked to metal dash, probe end stuck in the wire to the switch - try both wires, one should have power with the switch off, the other wire should have power with the switch activated.) If there is no power in the outgoing (load) side of the switch, then you need a new switch. You can jump the switch by joining the two wires (ingoing and outgoing) together to see of the pump operates I can't remember if there is a separate switch for the pump, or if it is integral to the wiper switch. There may be two outgoing wires, one for the pump and one for the wiper motor, so you might have to jump both alternately to see which one is the pump power. You may be able to remove the connector at the back of the switch and just jump the contacts to get the pump to work - same deal - attach the alligator clip to one contact and probe the other contacts. Make sure you use firm pressure on the probe and that the clip is hooked on there firmly. Be careful where you are poking that thing so you don't arc out something and blow a fuse. I am not sure if the switch gets its ground from being screwed to the metal dash - if so, then jumping the connector contacts probably won't work.

07-05-2014, 01:34 PM	#10
jd21476 Registered User Join Date: Aug 2013 Location: San Diego, CA Posts: 236	Re: Windshield washer problem Ok, Ill try that. Thank you __________________ 1973 Chevy K20

07-06-2014, 03:25 PM	#11
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,189	Re: Windshield washer problem If you go the the AutoZone website you should be able to search for a wiring diagram for your truck. You will have to sign up and log in, and maybe search for your year, make, model of washer pump first. It looks like there are multiple wires to/from the switch to the pump, but they do identify which one is ground so that should help. Unfortunately, they do not indicate which wires are for which function. My wire colors don't match the wiring diagram, so I don't know if the color scheme will help you much.

07-06-2014, 04:19 PM	#12
jd21476 Registered User Join Date: Aug 2013 Location: San Diego, CA Posts: 236	Re: Windshield washer problem So I did some troubleshooting on the switch and I think the switch is bad. I ordered a new one but the weird thing is that the switch is from a 1975 model and my truck is a 1973. __________________ 1973 Chevy K20

07-06-2014, 04:35 PM	#13
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,189	Re: Windshield washer problem Did you check the LMC website? http://www.lmctruck.com/icatalog/cc/full.aspx?Page=183

07-06-2014, 10:50 PM	#14
willett Another Day, Another Dollar Join Date: Nov 2008 Location: North Vancouver, BC Posts: 1,316	Re: Windshield washer problem There is constant hot to the pump, ground is switch controlled. __________________ -78 K20 Cheyenne 454 long box, 4" lift, 35" MT's, '84 cab, '80 box "its hip to be square"

07-07-2014, 03:16 PM	#15
KrazyRay Registered User Join Date: Jun 2009 Location: Oroville, CA Posts: 4,827	Re: Windshield washer problem There's a mod somewhere on this forum using a 85 an newer washer bottle that has the pump in the bottle. Its supposed to be much more reliable.

07-07-2014, 04:20 PM	#16
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,189	Re: Windshield washer problem Since I went with a Delco wiper motor/washer stock setup I have not had any problems in the past 12 years. I previously had bad luck with aftermarket motor/pump units. This is for my 83, so you have to get a motor with the pump as one unit. I think the earlier squares used a detachable pump. But the Delco is $98 vs. $50 for the aftermarket.



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