chris383

Hello,
I've almost complete my LT-1 reassembly. There still be some problems with my wipers system...
I've not found a red wire on the motor (number 4939300 which it seems to be correct for this year) to connect the wire from the wiper firewall switch.
I've seen several motor on the web with this red wire, but mine doesn't have this one :


Question
Where can I connect the wiper switch wire ? I've seen that it must be a hot wire : can I route a wire from the fuse box to power the switch ?

Thank you all.

Chris

gguillot

The red wire on the wiper motor comes from the top end, behind the washer pump housing. Here's the connection on my '72 LT-1. I pulled it out of the bundle so you could see it better.

Mooser

4939300 is just the casting or casing number, used on different years, I think up until 75 when they removed the mechanical washer pump but I don't know for sure. Looks like you've got a 73+ motor

The firewall switch just shut off the main 12v+ to the motor until the door was open and the switch depressed. One side of the firewall switch should be live (key in run) and the other side dead until the button is pressed simulating the wiper door opening.
You'll have to splice it into the feed somewhere on the way to the motor positive

HIH
M

Mooser

Sorry, looks like I read it wrong, thought he had the read to the switch but not the motor
M

gguillot

OK, that's kinda weird - looking at your picture, I've drawn an arrow where my motor power wire comes out the housing:

EarlyC34me

Mooser

He's definitely got a newer motor or one from another (Chevelle?) All the wiper-door motors had that extra red wire on the end (68 had two and I think maybe brown?)
Anyway
M

chris383

Thanks to ggouillot for the red line : it was too late yesterday to still do that ;-)
As Mooser said, I think also I have not a Corvette wiper motor. I can imagine that the red wire on motor is cpecific to Corvette because of the wiper door (and his switch).
I will hold my wiper motor for now, so I must find a solution to connect this red wire as Mooser told me. Unfortunately, I can't found any picture of my wiring before demounting it...
But which wire of the motor : any advice ?
Chris

gguillot

Here's a pic of the wiper motor from other GM models (Buick, Olds). It must still have the motor power and ground wire exiting the motor case somewhere. That is what you would connect directly to the red/white stripe wire from the microswitch.



GM Buick/Olds, etc. wiper motor

theandies

As stated you should have an extra red wire coming out of your motor since your car is a 1972 with the wiper door. My guess is over the years where this wire came out of the wiper motor changed whether it be original GM motor or the aftermarket that probably made 10s of thousands over the years.
If your motor doesn't have the wiper door safety switch wire then you either have the wrong motor or your wiper door has been deleted over the years. Since your asking my guess is you still have the wiper door.
You can disassemble the motor and install this wire. All it is is a break in the circuit to allow the wiper door safety switch be put in the circuit.
Here is the internal wiring:


The switch labeled limit switch (closed when lid is open) is the wiper door safety switch. Terminal connector is the red wire coming out of the motor so if you want to use your existing motor you need to install the connector here. The switch labeled Service Switch is the switch between the vacuum override switches under the steering column just for reference.

Here is what the inside of the motor looks like:


I have the 1969-72 wiper motor service manual in .pdf form if you want it. PM me.
Hope this helps

chris383

Thank you gguillot and Theandies for your help. I guess to buy a revised original motor (f.e the one from Willcox or ev. from Lectric Ltd ?) instead of modify mine : I wanted to do a revision of mine anyway.
After I saw the wiring diagram from Theandies, I guess the motor must have the gear box relay switch to connect the red wire : it is correct ? This switch is specific to Corvette motor ? Because the other cars don't need such separate switch or Am I wrong ?

0Willcox Corvette

The limit switch was put in place on the 69-72 cars to break the power feed to the motor while the door was shut. Without this the wipers would engage with the door down and destroy the arms. Your motor is either a later design or off another car and should have the limit switch wire coming out of the housing. If you look at the schematic below you'll see the wire (It's crude but a simplified schematic I've used for years).



Also, more wiper info on your car can be found at this link (wiper motor help) and here is a picture of the 1969-1972 motor.

69-72 wiper motor pictures.. both original and reproduction.

gguillot

Like Wilcox said, it looks like you just need the correct motor (or modify yours per theandies instructions.) As long as you still have the limiter microswitch in place - which I assume you do since the red wire with white stripe is there. It connects back to the switch here:
Red wire with white stripe (not spray bombed black like picture)

chris383

Exactly.The 2 wires on the connector that goes on this switch connector are : one in main firewall connector and one on the red wire motor, I have tested with Ohmmeter my switch and I assume it works. My wiper motor works also and my wiper door with manual override too. So I hope with a new motor this damn wiper system will at last work again !
Thank you for your help : as already said, this forum is a great help for me :-)

Chris

theandies

Hey Moser,
Did you install a relay to run the motor or just wire it up using the existing circuit? I'm just wonder about the increased current load a motor pumping water will create over a circuit that just energizes a coil to move and hold a metal arm.
I might go relay but I've used up all the space on my horn relay for my headlight relays and I really don't feel like making a buss bar at this time. This was going to be a quick "in between mods mod" because I'm knee deep into my Fiero seat conversion and am waiting on parts this weekend for that.

Mooser

The electric pump only draws about 1 amp so I didn't worry a whole lot and went right to the original switch. I don't know the draw on the original solenoid and although it was only momentary it would have been in the same range somewhere. I still have it here and I can check for draw after supper just to see what it takes.
M

theandies

I have a wiper motor solenoid but if you're not doing anything tonight............

I just started a 12 hour shift.

Mooser

1.3 Amps on the original solenoid
M

theandies

Thanks Mooser. Think I'll put an inline fuse just for piece of mind. 1.5 or 2amp fuse should provide adequate protection.

Mooser

I'd go 2 or 1.5 slo-blow
The washer circuit is fused but it's along with the radio or something strange
M