69 wipers wont open

[Pat Bush]

Re: 69 wipers wont open

Tom -

Well, you now know it does not appear to be a vacuum actuator or control problem if the door shuts! Usually they stay open (a GM fail-safe in case there was a problem) That's good news.

The engine does not have to be running for the wipers to work. You only have to have the key in the "on" position. It sounds like an electrical problem or the wiper motor itself has had it.That's what all that the switches and overrides are for under the driver side dash. Left side pull overides your headlight vacuum to open them. Right side pull should open the wiper door. And the center switch allows you to stop the wipers on the windshield for service.

First thing I would do is get myself a volt/ohm meter. Then you need to get a wiring diagram for a 69 or 70 (they are essentially the same car). You can get the GM service manual for the car here on NCRS. It's an excellent reference even after you are done with this job. Read the diagram, understand it, read it again, and then start testing from end to end everywhere you can.

Second thing I would do is check for a good ground to the wiper motor. No ground means no worky. You can add a temporary ground to the block and wiper motor to test with. See if that does it. Bad grounds cause more electrical problems on Vettes than on anything else I've worked on.

Third thing I would do is see if you have current to the wiper motor itself. I cannot remember which of the 4 or 5 wires supplies voltage -- you will need the wiring diagram for that. You should have 12V DC with the dash switch in first or second position. Please check to make sure the harness is connected to the wiper switch on the dash the correct way! You CAN reverse it and it will not work! Post on harness goes to post side of switch.

If you do not have current to the wiper, you definately have either a broken wire somewhere in the harness (oh goody) or a bad wiper switch or the wiper relay is not working. The good news is you are not blowing a fuse so you can at least be pretty sure there is no dead short (that would be real bad).

If you have current to the motor, a good ground, and the motor still isn't working, it could still be the wiper relay or it could very well be the motor itself. The wiper relay is located under the passenger side access panel and is bolted to the console. You can test for input/output voltage there as well.

One can only hope for an easy fix. Otherwise, be patient and test each piece of the circuit one step at a time. You'll get it.

Regards -

Pat

[Jim T.]

Re: 69 wipers wont open

Tom one more switch to try. Disconnect the vacuum hoses from the vacuum cannister and open the cowl wiper door manually. You should be able to see a electical switch on the right side of the vacuum cannister. This switch is activated by a metal arm when the wiper door comes open and this switch permits power to the wiper motor. If the arm is not making full on contact with the switch when the wiper door is opened or the switch is bad, your wipers will not activate.

[Tom S.]

Re: 69 wipers wont open

Jim
I will try this as I was working on the wipers this afternoon and did not make much prgress. I have had the door open manully. WHEN I TURN ON THE WIPER SWITCH I hear aclick sound up at the wiper motor. Then the door closes.I do think I have an electrical problem.My vacuum canister is tucked inside the left fender well.Are you talking about this cannister? If so is the switch near the canister or under the wiper door I was not to clear on that. It sure sounds like a reasonable idea.I bought a trouble shooting guide for wiper and headlights from corvette conection but it was basicly worthless. Not much help at all. Please answer back on my questions andI will try it. Thanks again for all your help.
Tom

[Tom S.]

Re: 69 wipers wont open

Jim
I also failed to mention I put in a new electric override switch I thougt it might have been the problem but it made no difference.Also when I pull the wiper door override it does not open the door. I have to do it from under the hood.The override switch seems to be in good shape.I put in a new one for the headlights 39.00 for that little plastic switch seems a litte steep. please advise.
THANKS AGAIN TOM

[Tom S.]

Re: 69 wipers wont open

To all who have helped
I have power to the motor ,I hear a click at the motor when I turn on the switch. I have run a ground wire from the motor to the block.when I was checing the motor today I felt a lot of heat from a valve I geuss it ismounted on the d s of the motor that has a wiring harness pluged into it and a vacuum line coming off it. I don't know what it is but it gets quite hot with the switch on.Is the motor shot? thanks

TOM
Ican't find a picture of this valve in chiltons, ecklers or corvette central maybe it is not serviced seperately?

[Jim T.]

Re: 69 wipers wont open

Tom the electrical switch I mentioned in my earlier post is mounted on the firewall. On the right side of the vacuum canister, the one that opens and closes the wiper cowl door, is the location of the switch. The arm that activates the switch button comes from under the cowl/grill and through the firewall. It has a adjustment on it. The switch has large guage red wire with white stripes going from the switch to the wiper motor. The location is between the vacuum cannister and the wiper. The arm moves when the cowl is raised. When the cowl is up is the only time that the switch allows power to the wiper motor.

[Pat Bush]

Re: 69 wipers wont open

Tom --

I'm going to go out on a limb here.... Heat from any component in the electrical system is usually not good. You need to look for any wires in that area that may have grounded out or have cracked insulation..... It usually indicates a dead short (sort of how a toaster works). You need to find the cause of that in a hurry -- you can ruin a wiring harness quickly as well as the components in-line and if bad enough, cause a fire.

The 'click' would seem to indicate you are getting power to the motor but it is possible that the windings are bad in the motor itself or the switch is faulty and it is causing a dead short which is generating the heat. Is the wiper motor seized?

I am having trouble understanding what component is generating heat from your post. Perhaps you can post a picture of the component? It sounds like the wiper door switch Jim is talking about in his posts but without a picture its hard to understand what you are looking at. There are several relays on the firewall including TCS (not the likely culprit), power window (also not likely), and the door switch (likely). LS is drivers sidel; RS is passenger just so we are on the same page.

I think you are getting close to finding the problem though..... Give us some more info and maybe we can isolate it. Do as Jim says and try to manually actuate the switch -- see if that makes it go. If you have current to the motor and switch assembly, it would stand to reason, it is one of those two pieces that is faulty.

[Tom S.]

Re: 69 wipers wont open

Pat
The switch that i am refering to is onthe left front of the wiper motor. It has a blue and a yellow set of wires on a plastic connector pluging into it. THERE IS ALSO 2 BLACK WIREs GOING TO IT. A VACUUM hose comes off from it and it has 1 small bolt or screw and 2 straps holding it to a white plastic something on the wiper motor itself. It gets hot in 20-30seconds.I am wondering if the wiper motor is frozen up. I have tapped on it, tried to pull gently on the wiper arms but nothing, I do not know what this valve is, but that is one sure problem. I have found the valve Jim was refering to I have not gotten any further with that one. Thanks one and all for your help and perserverance.

Tom Stanton

[Dan M.]

Re: 69 wipers wont open

Tom,

Just wanted to offer a great book as a reference source CORVETTE Weekend Projects Maintenance and repairs How Tos for 1968-1982 by John Pfanstiehl published by HPBooks page 31-37 and page 118. Email me and I'll send you the link to the Barnes and Noble site for the book.

Dan

[Pat Bush]

Re: 69 wipers wont open

Tom -

I went out and looked at my 70. Dude, I can't for the life of me figure out what this thing is that's on your car! I looked at my wiring harness and wiper motor-- I have a light blue, yellow, and light green connector at the base of the wiper. One black ground wire slightly above that. That should be what drives the motor. The only thing with "vacuum" coming out of it on the washer would be the wiper pump and I wouldn't think that is your problem. I just can't locate the part you are describing.

It seems to me that the motor itself may be the problem but it's awful hard to tell without actually being there and seeing what you've got. You may want to bite the bullet and let a mechanic look at it at this point. Wish I could be of more assistance....

Pat

[Tom S.]

Re: 69 wipers wont open

Pat
I am going to let a mechanic look at after this weekend if I can't figure it out.Dan told me about a switch that I didn't even know was there. Its thevacuum control valve under the cowl. The vacuum hose are dry rotted and the boot on the valve is shot. I will put this on anyway and who knows. But after that I am leaving this up to a pro.
Thanks Tom

[Terry M.]

Re: 69 wipers wont open

Tom & Pat,
The 1969 windshield washer pump is very different than the 1970 unit, and it sounds to me like Tom is describing one part of the 1969 WW pump. My guess is that the "vacuum" lines are really either the windshield washer or headlight washer hoses, and the part that is heating may be the washer solenoid that is mounted on the driver's side of the 1969 WW pump.
This is a case where a picture would be worth a lot of words, because without that we are the blind person describing the elephant.
FWIW: There are lots of good pictures, along with the proper terms for various parts in the Factory Service Manuals (FSM). They are worth their weight in gold. For a lot less than that you can get them from the NCRS store - Click on the buttons on the top of the page. - Shameless plug for what supports this site.