Wiper door mechanism

[CaptainK]

I'm currently doing an electric wiper door conversion on my 1968, slowly over time because of well.... "1968" issues, "bubba" previous owner, and also I have a baby taking up a lot of time.

Anyway, I've currently got the wiper door mechanism off the car for various reasons. As you can see from the photo, the previous owner oversprayed it blue when the car was resprayed ages back. I don't mind it being blue, but its not massively consistent. Granted you won't see the current black bits where the fixing brackets and screws are as they are hidden within the bulkhead thingy. To be fair, most of it you don't see as the wiper door and grill covers it.

I was wondering what colour the wiper door mechanism was originally? I'm tempted to rub it down and respray it.

 

[Emc]

Originally it was satin black

 

[Mr. Cricket]

Great fun coming your way reinstalling the wiper door. I took mine off the '71 just to clean up the mess under there and what a pain it was getting it back on.

Another conformation it was satin black

 

[CaptainK]

Nice one, thanks both

 

[CaptainK]

Re-installed the wiper door and the physical side of it went really well. Then it all went downhill as my previously working (but hadn't been connected up to linkage) wiper door electric conversion stopped working, and the wiper door override light is permanently on. Got the motor working again, but ran out of time to investigate "override" bulb. Gotta be a short or something somewhere, as it was working fine beforehand. All fun and games really isn't it? I think I might have an idea, but getting chance to have a look is hard. Too busy!

But if anyone has any ideas what the bits on this wiring diagram is that'd be great - i.e. the ground wire from the "over ride switch" (bottom right) goes up to a upside down "T" shape thing in the top left corner, next to the firewall limit switch bit (I know where that is in the engine bay, and in the 1968 only that only ever has ground through it 0 69 onwards its positive). But what does the symbol mean? And what is the component? Unhelpfully it then leads that to another symbol just below it that looks like "Stone henge". What component is that? Both of those black wires from "Upside down T" and "Stone Henge" both go to the override lamp you see, which illuminates when it gets 12 volts. So evidently 12v is now going down it from somewhere. If it helps, its from a permanent live - turns on when I reconnect car battery (normally disconnected).

 

[teamzr1]

Re-installed the wiper door and the physical side of it went really well. Then it all went downhill as my previously working (but hadn't been connected up to linkage) wiper door electric conversion stopped working, and the wiper door override light is permanently on. Got the motor working again, but ran out of time to investigate "override" bulb. Gotta be a short or something somewhere, as it was working fine beforehand. All fun and games really isn't it? I think I might have an idea, but getting chance to have a look is hard. Too busy!

But if anyone has any ideas what the bits on this wiring diagram is that'd be great - i.e. the ground wire from the "over ride switch" (bottom right) goes up to a upside down "T" shape thing in the top left corner, next to the firewall limit switch bit (I know where that is in the engine bay, and in the 1968 only that only ever has ground through it 0 69 onwards its positive). But what does the symbol mean? And what is the component? Unhelpfully it then leads that to another symbol just below it that looks like "Stone henge". What component is that? Both of those black wires from "Upside down T" and "Stone Henge" both go to the override lamp you see, which illuminates when it gets 12 volts. So evidently 12v is now going down it from somewhere. If it helps, its from a permanent live - turns on when I reconnect car battery (normally disconnected).

Would be easier to read if you break up in smaller sentences you wrote as hard to follow as you have it
And the schematic is confusing and not sure if it is correct

I assume what you mean by upside down T at top left is the connections to the limit switch
Do not know what "Stone henge" means but if you mean right below limit connections
I think that means where the relay shown on right connections

Look at the blue arrows I inserted and as to the notes at bottom follow the black stars I inserted

I made the black and blown lines for override wider to easier to follow those wires

The red boxes you have on top right, that light gets 12 volts when limit switch is in open position
Make sure the over-ride switch at bottom right is wired and functional

Make sure the limit switch is wired correctly and I assume when wiper door is fully shut it hits the
top of limit switch to push down the button on top to open the circuit

 

[CaptainK]

Thanks Team, and sorry for my waffle.

This bit is the "Upside down T" below the word "Ground":


I can see that the "Upside down T" on the right is for the Firewall Limit Switch (which is ground based on a 1968), but didn't know what the left hand side "Upside Down T" was.

By "Stonehenge", I'm referring to these that are just below the bit above:

I can't work out what actual physical component that was supposed to be representing, and more to the point where that component is.

But looking at the diagram again after your labelling has made me realise the blimmin obvious wording at the bottom that says "If the ground has fallen off the override switch bracket then the override lamp will illuminate". So that's probably a good thing to check. And there I was trying to focus on the components in the diagram and what I might have upset when wiggling wires around, and missed the obvious text at the bottom.


Oh and in case you wanted to know why I called it Stonehenge, it looks a lot like the stones at Stonehenge (famous landmark in the UK) - aka the two pillars with a stone on top:



Oh and in case anyone wanted to know, I believe Corvette changed the wiper wiring from 1968 to 1969 from ground based switching to positive switching because on 1968 the wiper motor is always positive connected even when the key is out of the car. So the battery goes slowly flat. Swap it around to positive switching and all good. Well, just a theory I read and it makes sense. I keep my battery disconnected anyway when car not is use.

 

[teamzr1]

Maybe the T and hinge is terminal blocks on the firewall that the wires connect to ?
Or is where relay is wired to ?

In any case take an Ohm meter and one of the probes connect to the over-ride switch shown at bottom right
and other probe to the brown/white wire at one side of the limit switch and make sure that wire is good

Take one side of OHM meter to one side of the limit switch and other probe to the other side of the switch and see what the meter shows and then press the button on top of the switch and see if that works correctly

With key on, engine off, when you press down on limit switch does the over-ride light go on and off ?

Does the 12 volts using a multi meter for D/C voltage show 12 volts when the limit button is pushed and then no light when not pressing the limit switch button ?

 

[CaptainK]

Thanks Team. Only just seen your post, but I went out to the car quickly yesterday for a tiny bit - don't get much time to play at the moment for various reasons. Its taken months so far already to get to where I am .

I hadn't done any changes under the dash, but yesterday I looked under there and it does have a black ground wire on the bracket there, which I guess is "A" on the diagram above. According to my multimeter, that seems to be fine.

I've also checked my new wiring in the engine bay with my multimeter and they seem ok - all I've done is add connectors to existing wiring to get the trigger signal, a 12v feed and a ground. So nothing too complex.

Silly me I forgot to check wire "D" from the over-ride switch under the dash. I mean I was right there testing the bracket for it too!

One thing I did forget to mention before, that the wiper override lamp comes on as soon as I connect the battery. As soon as the connector touches the battery you can hear a faint "clunk" sound as something activates. I don't know if its a relay or a solenoid as my arm isn't long enough to stretch into the battery compartment and listen at various places at the same time.

 

[teamzr1]

Really think you need to test and see if that light goes off when using the over-ride switch and
also hold down the button of limit switch and see if light changes state

Is that limit switch normally open or closed when testing with an OHM meter when not pushing on that button and then
when holding button down ?

 

[CaptainK]

Was away over the weekend, so couldn't play much. I did test a few more circuits for power, including over ride switch, firewall limit switch, grounds to them etc. None of the switches made any difference - the wiper override lamp stays on, and more critically the wipers don't work.

I've run the engine up too in the vain hope it was down to lack of vacuum etc. But sadly not. I suspect what has happened is the issue I was trying to fix has made itself worse. Previously when the wipers were activated, the wiper over ride lamp would very very lightly flicker, and the wipers weren't that fast. It has to be a bad ground somewhere, but I just can't find it.

I'll have another place when I get chance, probably tomorrow, unplugging things and testing circuits etc to see what happens.

Oh and to top it off, my multimeter seems to have gone weird / died - I was testing circuits all fine, when suddenly it was just reading "0.04" when I was expecting 12v. Thinking I'd found the problem with the car, and kept tracing issues, I checked the battery itself and that too was "0.04". Thinking I then might have a buggered battery, I checked it on one of my other cars - yup, "0.04" on that too. Urgh.

 

[Mr. Cricket]

Change the batteries in the meter

 

[CaptainK]

Change the batteries in the meter

Yeah, that was my thought too, but yet to do as lack of time. I do have another multimeter somewhere though in case the main one is dead.

 

[johng]

Have you inadvertently pressed the peak hold button on the meter?

 

[Mr. Cricket]

Yeah, that was my thought too, but yet to do as lack of time. I do have another multimeter somewhere though in case the main one is dead.

I had one do the same, fresh batteries fixed it so hopefully your's too

 

[CaptainK]

I had one do the same, fresh batteries fixed it so hopefully your's too

Fingers crossed. To be fair, it is about 20 - 25 years old on its first battery, and whilst I was doing this diagnosis I was pondering if the battery would give up

As for my wiper issue..... its is FIXED

My father in law is currently staying with us, which meant I managed to get some time last night to tinker as he could help wifey with the child. I would like to say it was my brilliance that found the fault, but actually it was dumb luck. I was using my newer (possibly better) multimeter as the old one is dead (as above). I was testing the connections to the wiper override switch and bracket etc, and had unplugged all the wiper motor stuff previously.

So I had the probes in the override switch and was playing with the knob (AWWW MATRON!) like I did the other day, and by pure chance I noticed a very slight decease in voltage on the brown/white wire coming from the override as I was moving it from on to off. Playing with the knob more it seems my override knob is a bit dodgy - neither on nor off work, but some random place part way between the two does the job. So I left it there and activated the wiper switch. Nothing...... because of course I had everything disconnected.

Unplug battery, reconnect wiper stuff, put battery on and hear it "park" the wiper motor (I think) and no "CLUNK" from a solenoid when I put the battery on. Activate wipers, all works fine.

TL;DR:
My wiper override switch is dodgy, and I think my wiper was stuck wanting to open, and needed to park. I'll need a new override switch at some point, but being a 68 only part, it'll probably be expensive. It turns out you can just connect the wire to ground and it'll be fine, and pull the wire off when you want the wipers to be overridden. So I'm tempted to just put it to ground.

Thanks everyone for the help

 

[CaptainK]

Have you inadvertently pressed the peak hold button on the meter?

Anything possible I guess. But I don't think that multimeter has a hold button. I'll check next time though - thanks for the heads up.

 

[teamzr1]

You could first try using an electronic spray cleaner to that over-ride switch
Use Ohm meter with 1 probe on case of switch and other on that 1 wiring lug and turn the switch
and see what the resistance value changes as turning the knob

Would be easier than to buy any potentiometers type switch to replace old one

If need be use one that has 2 wiring lugs where one goes to ground and other is connected to the brown//white wire

 

[CaptainK]

If need be use one that has 2 wiring lugs where one goes to ground and other is connected to the brown//white wire

Yeah, I probably would just use a 69 onwards two pin pot switch, or a random cheap pot switch if I did it. I've been using "random" parts to fix my wipers already as refuse to pay tons of money for things that are just "eye bolts" and "plastic bushings" and "bolt connectors" etc.

Fail that, like I said above, I might just put the brown/white wire straight to ground on a switch or connector block and then just disconnect it when I want to use the override.

 

[CaptainK]

The plot thickens.... the wiper override is back to being on all the time, and wiper doesn't work. Urgh.

Managed to find a tiny bit of time to look at my override switch over the weekend. Took it out, run the multimeter over it and it has continuity when expected, and no continuity when not expected. So all works fine and dandy.

After much "FFS" and playing and so forth I happen to again struck luck. I had jury rigged up a bypass to the override switch, and it too wasn't fixing the problem. I was testing continuity all through the override bracket to ground etc too. It was only when testing with my jury rig I think I've found the problem - loose brown/white wire going into the connector that connected to the override switch. Previously it must have been bad luck it was connecting fine because I'd shoved the multimeter probe in there.

Anyway, it was at that exact point in life when wife came in and handed me the baby as she needed to do stuff. So I'll have to confirm my suspicions later - I'm HOPING its the wire connector on the override switch end, and not the other end wherever that wire goes to (wiper relay in dash I think - which is a PITA to get to I'm told). On the plus side, when it does all connect and work, the electric wiper door system is beautiful.