wiring problems
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Joined: Sep 2009
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wiring problems
My horn,wipers,and blower motor on my 72 arent working... The horn and wipers havent worked since I bought the car, and the blower motor worked sporadically,but now doesnt work at all. Ive just started to look into the problems and was wondering if there was a common ground or relay to some of these circuits. I just bought the car in August and have noticed that some of the wiring under the dash has been messed with,but it doesnt look too bad. Before I go and buy all new harnesses or do something crazy,I would like to know if there is a good place to start troubleshooting. Any help would be appreciated. Thx
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Joined: Feb 2005
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From: Crisfield Maryland
Burning Brakes
Joined: Nov 2006
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From: Orange Park Florida
Pick up a wiring diagram. Then look for a missing ground that feeds the wipers, fan, and AC (if installed). Check at the starter for a small black wire that is connected to the battery/hot terminal instead of the starter ground. That's where the ground originates. Good luck.
Team Owner
Joined: Sep 2006
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From: Westminster Maryland
Hi P72,
Have you checked the fuses?
There are MANY reasons your wipers aren't working... both vacuum and electrical. Does the wiper door open? Is the round switch directly below the steering column turned to on? If that's turned to off the wipers stay right where they are no matter what you do with the wiper switch on the dash.
The blower motor and horn are a bit easier to troubleshoot.
What have you tried?
Regards,
Alan
Have you checked the fuses?
There are MANY reasons your wipers aren't working... both vacuum and electrical. Does the wiper door open? Is the round switch directly below the steering column turned to on? If that's turned to off the wipers stay right where they are no matter what you do with the wiper switch on the dash.
The blower motor and horn are a bit easier to troubleshoot.
What have you tried?
Regards,
Alan
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Alan,I checked the fuses and they are fine,even replaced them just to make sure.When I turn on wiper switch,the door opens fine,and Ive tried it with the **** under column in both positions. I know those ***** are famous for going bad,so Ill pull it out and test it.When I looked under dash,I noticed the red and white wire from the **** to the fuse block was cut and spliced with another piece of wire that someone ran through the firewall to the rubber 2 wire plug that i believe is for the safety switch for the wiper door.I found where the red and white wire was cut under dash and in engine compartment and reconnected the wires the way they sould be. Still have a working wiper door but no wipers. Thanks for your help on this one,as I just bought the car in August and its finally warm enough to start working in it,Im fairly new to Corvettes and Im finding out quickly that theyre kinda quirky.
Instructor
Joined: Sep 2008
Posts: 222
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From: penngrove ca
You need 3 things, wiring diagram, trouble light and meter. I purchased a 2'X3' laminate wiring diagram for $10.
Trace and repair each circuit individually source to device.
Doesn't sound like you have common ground probelm since the heat fan worked at least for awhile, while others never did.
Speaking from experience when someone has worked on it before all kinds of learning experinces are in store.
Trace and repair each circuit individually source to device.
Doesn't sound like you have common ground probelm since the heat fan worked at least for awhile, while others never did.
Speaking from experience when someone has worked on it before all kinds of learning experinces are in store.
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ripforrey,tell me about it..I owned a 67 GTO in H.S. and someone thought they could rewire the car better than GM. After 3 years,I finally gave in to the evil Elvis spirits and sold it. Just ordered the AIM manual and asked papawana for some electrical diagrams for my car today and hopefully Ill get it sorted out...Hopefully Ill have more patience than when I was in H.S....Thx
Team Owner
Joined: Sep 2006
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From: Westminster Maryland
HiP72,
If the wiper door opens the next thing to check is the little button switch on the firewall just to the right of the engine. A 'finger' rod comes out through the firewall, it's attached to the wiper door mechanism. That finger needs to depress the button switch to signal the wiper motor that the door is open and it's o.k. to start the wipers.
Try It!
Regards,
Alan
PS: Buy a G.M. Chassis Service Manual for your car too. There's one for each year, lots of vendors sell them
This is it looking from above. Ignore the oval, it's showing a vacuum hose routing.
If the wiper door opens the next thing to check is the little button switch on the firewall just to the right of the engine. A 'finger' rod comes out through the firewall, it's attached to the wiper door mechanism. That finger needs to depress the button switch to signal the wiper motor that the door is open and it's o.k. to start the wipers.
Try It!
Regards,
Alan
PS: Buy a G.M. Chassis Service Manual for your car too. There's one for each year, lots of vendors sell them
This is it looking from above. Ignore the oval, it's showing a vacuum hose routing.
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Thread Starter
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Hi Alan, Ok when I turn wipers on,the button switch depresses like it should.I checked voltage on yellow and blue wires at the wiper motor and theyre both at 11.84V with the wiper switch on. However the red and white wire that runs from the button switch to the red wire on the wiper motor has nothing. Am I doing this right?
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Ok,first rookie Corvette mistake..I went and turned the **** under the steering column and now I have 12V to the red and white wire going to the red wire on the wiper motor also...If I have power to the blue,yellow,and red wires on the wiper motor,shouldnt it be working?
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Alright,I went to the Wilcox site and downloaded their file for testing my wipers...the wiper switch,bypass switch,and limit switch, all seem to be fine,and when I hard wired the wiper motor,it worked perfectly...I checked the ground wire at the starter and it is bolted securely to the bellhousing...Now Im lost as to what to check next...Is it the wiper relay,or a ground somewhere I dont know about?..My blower motor also doesnt work and also,when I dropped the wiper switch plate from the center bezel,I could hear a clicking from under the dash when I would jiggle it against the bezel loosely along with a small spark where it was making contact,is this normal? Any help would be greatly appreciated...Thx,Mike
Race Director
Joined: Mar 2006
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From: Florida
The oem engine compartment harness has a pretty cheezy ground system at best. They used very small ground wire 16ga if I remember correctly.
There is a junction inside the harness roughly behind the distributer where it branches into other grounds, wiper motor, starter, high fan relay, blower and hood alarm.
If at one point, the starter ground wire was connected to the starter battery trnminal by mistake, the ground wires/and/or junction could have melted or burnt thru.
You can use an ohm meter to test all ground wire ends to ground, although that won't tell you of the ampacity.
If you find the ground system bad, then just rebuild with 12 ga wire, especially to the starter ground and blower and relay.
There is a junction inside the harness roughly behind the distributer where it branches into other grounds, wiper motor, starter, high fan relay, blower and hood alarm.
If at one point, the starter ground wire was connected to the starter battery trnminal by mistake, the ground wires/and/or junction could have melted or burnt thru.
You can use an ohm meter to test all ground wire ends to ground, although that won't tell you of the ampacity.
If you find the ground system bad, then just rebuild with 12 ga wire, especially to the starter ground and blower and relay.
Thread Starter
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Thx for the info guys..Is that junction for all the grounds the one that runs to the starter,or in my case,the bellhousing? Also Ive been looking at the wiring diagram and it says that there is a dash ground. Where would this be located? Thx, Mike
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steering column wiring? Heeeeelp!!!
This problem is driving me nuts!!!!! I looked at everything I possibly could,to try and get my wipers working but still...nothing..I decided to check the horn and the blower motor by hard wiring them and they both work. The ground wire by the starter is securely bolted to the bellhousing. Also when the drivers door is open,the key buzzer goes off with no key in the ign. but the interior lights dont come on.. I put a new door jamb switch in and the same thing happens...When I jiggle the switch,the buzzer stops and the interior lights will come on,but if I tap the dash or steering column,it buzzes again...Is it possible/likely that I have a short somewhere under the dash or in the steering column,or is there something else im missing? Im thinking all these problems are all related...Any help would be greatly appreciated as I cant sleep or eat,and when I close my eyes,all I see are wiring diagrams..I find myself staring blankly into space all day or checking behind me for evil spirits....
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From: mount holly NC
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Also when the drivers door is open,the key buzzer goes off with no key in the ign. but the interior lights dont come on.. I put a new door jamb switch in and the same thing happens...When I jiggle the switch,the buzzer stops and the interior lights will come on,but if I tap the dash or steering column,it buzzes again...Is it possible/likely that I have a short somewhere under the dash or in the steering column,or is there something else im missing? Im thinking all these problems are all related.
One wire is the ground to make the courtesy lights glow.
The next wire grounds the "Key left in the switch buzzer. You say the buzzer is on without the key in it, that is caused by either the "tab" on the key cylinder not working properly or the switch that the tab activates (inside the column) is not adjusted properly.
The third wire on the door jam switch activates the alarm.
You have to buy the "Correct" door jam switch and the "Special" connectors to go with them.
