Electrical gremlins....
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Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Electrical gremlins....
Ugh. Thought I was done with all my problems. Not quite.
Anyway, 1985 Corvette, windshield wipers intermittently will not shut off. When this happens I think they are stuck on the low setting, and if I switch it to delay, doesn't slow down. If I switch it to off, doesn't shut off. But if I switch it to high, it will go to the high speed, and if I switch it to any other setting it will go back to low.
When that happened, I noticed that my heat was not longer blowing. I switched it the defroster, and nothing came out of there. When I switched the settings back on fourth on the HVAC controls, I heard a vacuum sucking sound. I thought it was my check valve in the engine bay, so I turned the HVAC off, shut the engine off and pulled the hoses off the check valve and I did hear a vacuum sound so it's holding vacuum. This is the manual HVAC controls by the way, the ones with the sliding levers.
Whats strange is that when the wipers did finally shut off, the heat started blowing harder than it ever did. And all the HVAC controls worked.
So is there any grounds or wires or anything that these two systems share? I don't have access right now to wiring diagrams or I would figure it out myself. Or is there common problems for these things?
Thanks a lot guys!
EDIT: Also forgot to mention. The heat was blowing out of the vents and the defroster (whichever one I selected), when the car was driving. When it was idling, nothing was coming out.
Anyway, 1985 Corvette, windshield wipers intermittently will not shut off. When this happens I think they are stuck on the low setting, and if I switch it to delay, doesn't slow down. If I switch it to off, doesn't shut off. But if I switch it to high, it will go to the high speed, and if I switch it to any other setting it will go back to low.
When that happened, I noticed that my heat was not longer blowing. I switched it the defroster, and nothing came out of there. When I switched the settings back on fourth on the HVAC controls, I heard a vacuum sucking sound. I thought it was my check valve in the engine bay, so I turned the HVAC off, shut the engine off and pulled the hoses off the check valve and I did hear a vacuum sound so it's holding vacuum. This is the manual HVAC controls by the way, the ones with the sliding levers.
Whats strange is that when the wipers did finally shut off, the heat started blowing harder than it ever did. And all the HVAC controls worked.
So is there any grounds or wires or anything that these two systems share? I don't have access right now to wiring diagrams or I would figure it out myself. Or is there common problems for these things?
Thanks a lot guys!
EDIT: Also forgot to mention. The heat was blowing out of the vents and the defroster (whichever one I selected), when the car was driving. When it was idling, nothing was coming out.
Last edited by DanielRicany; Oct 23, 2014 at 04:59 PM.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
So many things to check...you will need to get the wiring diagram and begin testing. I do know that the outer cover for the wiper motor can fail...which can cause many problems.
It seems like you have NO vacuum getting to your AC/heater head...knowing that you are manual controls...CORRECT??? You have to listen for a vacuum leak....and if my memory serves me correctly...the vacuum tubing gets routes in the split loom material and goes down to the starter and then into the car. And the junction is to the right of the radio...above the close out panel where your footwell light in it.
Also there it a special vacuum check valve normally located to the right of the wiper motor that makes it so your vacuum storage ball in froth of the drivers front wheel area can hold vacuum....and if I am not mistaken...also does the cruise control vacuum also. if the check valve is bad.,..that is not good....and any hose that is open ...is not good.
DUB
It seems like you have NO vacuum getting to your AC/heater head...knowing that you are manual controls...CORRECT??? You have to listen for a vacuum leak....and if my memory serves me correctly...the vacuum tubing gets routes in the split loom material and goes down to the starter and then into the car. And the junction is to the right of the radio...above the close out panel where your footwell light in it.
Also there it a special vacuum check valve normally located to the right of the wiper motor that makes it so your vacuum storage ball in froth of the drivers front wheel area can hold vacuum....and if I am not mistaken...also does the cruise control vacuum also. if the check valve is bad.,..that is not good....and any hose that is open ...is not good.
DUB
