1971 Wiper Problem
Thread Starter
Heel & Toe
Joined: Jul 2002
Posts: 20
Likes: 0
From: New Boston NH
1971 Wiper Problem
I need help with a wiper problem. The switch on the center dash doesn't work, but used to last week. I can open the cowl with the vacuum release pull under the steering wheel, but the manual *** won't activate the wipers. The fuse is good and I get 12V on both sides of it. I get 12V to the manual *** and 12V on the other side when the key is on. I traced that wire up to the wiper motor, there's a quick connect before it goes in, and there is 12V there. I'm assuming the motor is getting power. My guess is that the either...
1. The motor is bad. or
2. The relay that disables the wipers from operating until the cowl is open is bad, therefore the wipers won't work since it thinks the cowl is still closed.
Where is the relay or switch or whatever that disables the motor until the cowl is open located?
How can I bypass the switch to test the wiper motor?
Any help would be appreciated. Thanks!
1. The motor is bad. or
2. The relay that disables the wipers from operating until the cowl is open is bad, therefore the wipers won't work since it thinks the cowl is still closed.
Where is the relay or switch or whatever that disables the motor until the cowl is open located?
How can I bypass the switch to test the wiper motor?
Any help would be appreciated. Thanks!
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Re: 1971 Wiper Problem (kennersonm)
Kenner, just to the pass side on the firewall next to the wiper motor is a hook looking protrusiion from the wiper door mechanism, this hooks down with some adjustment screws on it, intersecting a red push button switch, with 2 heavy red wires on it, plug is about an inch diameter into the wiring harness, the harness is red and red/white traceer....anyway, one of those wires then goes to the WSW motor,....
just unplug the rubber plug/jack and jumper the harness end closed for continuous operation...but keep in mind the door has to be open or you can mess up the wipers but good...maybe even break the door....
the elementary logis of the vacuum relay controlling the door operation is the small controll hose...if it's under vacuum, door closes, so it's suck down....
if no vacuum is present the vacuum relay changes state, and opens the door by switching large vacuum power lines to the cannister motor/actuator....
headlights, same logic pattern....
small controll hose has vacuum....wiper door and headlights are down,...otherwise they should be UP....
GENE
just unplug the rubber plug/jack and jumper the harness end closed for continuous operation...but keep in mind the door has to be open or you can mess up the wipers but good...maybe even break the door....
the elementary logis of the vacuum relay controlling the door operation is the small controll hose...if it's under vacuum, door closes, so it's suck down....
if no vacuum is present the vacuum relay changes state, and opens the door by switching large vacuum power lines to the cannister motor/actuator....
headlights, same logic pattern....
small controll hose has vacuum....wiper door and headlights are down,...otherwise they should be UP....
GENE
Instructor
Joined: Mar 1999
Posts: 158
Likes: 0
From: Lakeland FL
Re: 1971 Wiper Problem (kennersonm)
Kenner,
What are the multimeter readings on the three-wire inline connector at the wiper motor? Please take readings on all three pins with the wiper switch in the off, low and high positions.
It sounds like you have main power to the wiper, but there is a small solenoid inside the wiper assembly that controls the main power. The solenoid is closed when the dash mounted wiper switch provides a ground.
If power is supplied to the solenoid through the center pin and ground provided through the leftmost( on my car) pin you should be able to hear the solenoid click. If it clicks and you still get no wipers the solenoid maybe burnt out. If no power/ground is available at the three-wire inline connector then another component is causing you grief.
Please post your findings as I am gathering information on the changes in the wiper system operation through the years.
:cheers:
What are the multimeter readings on the three-wire inline connector at the wiper motor? Please take readings on all three pins with the wiper switch in the off, low and high positions.
It sounds like you have main power to the wiper, but there is a small solenoid inside the wiper assembly that controls the main power. The solenoid is closed when the dash mounted wiper switch provides a ground.
If power is supplied to the solenoid through the center pin and ground provided through the leftmost( on my car) pin you should be able to hear the solenoid click. If it clicks and you still get no wipers the solenoid maybe burnt out. If no power/ground is available at the three-wire inline connector then another component is causing you grief.
Please post your findings as I am gathering information on the changes in the wiper system operation through the years.
:cheers:
Instructor
Joined: Mar 2002
Posts: 238
Likes: 1
From: Conyers GA
Re: 1971 Wiper Problem (TerryN68)
Kenner,
Don't forget the ground at the wiper motor. I had the same type of problem with my '72. I had power, but no wipers. I ran a "bubba" ground from the dist shield to the wiper motor, and it would work.
After a bit of checking, I found that the ground wire that attaches to the wiper motor assembly (black wire) runs down the pass side of the engine to a bolt on the bellhousing. This wire had come loose (old age?) and wasn't getting a good ground. Removed the bolt, installed a new end on the wire and re-installed. Everything works OK now.
Just a thought.....
Oh yea....just so I don't get "Bubba'd", I did remove the wire from the dist shield...it was there just as a test!!!
[Modified by Martin72, 1:35 PM 7/25/2002]
Don't forget the ground at the wiper motor. I had the same type of problem with my '72. I had power, but no wipers. I ran a "bubba" ground from the dist shield to the wiper motor, and it would work.
After a bit of checking, I found that the ground wire that attaches to the wiper motor assembly (black wire) runs down the pass side of the engine to a bolt on the bellhousing. This wire had come loose (old age?) and wasn't getting a good ground. Removed the bolt, installed a new end on the wire and re-installed. Everything works OK now.
Just a thought.....
Oh yea....just so I don't get "Bubba'd", I did remove the wire from the dist shield...it was there just as a test!!!
[Modified by Martin72, 1:35 PM 7/25/2002]
Thread Starter
Heel & Toe
Joined: Jul 2002
Posts: 20
Likes: 0
From: New Boston NH
Re: 1971 Wiper Problem (kennersonm)
They're fixed - I'm so happy.
I tried several paths, but finally had an extremely simple problem. The motor ground was good, and I had continuity through all the wires. (Terry - thanks for the schematics, they're utlimately what helped). I took apart the dash switch, it needed cleaning but was ok. The limit switch for the cowl being open was working fine. I even tried to pull the wiper motor to bench test it but the wiper transmission would not budge off the motor shaft, the nut came off fine but the linkage arm is frozen. I put that idea aside.
Going back to the schematic and saying OK power starts here - I found the yellow jumper wire in the front of fuse block was loose and not passing the voltage on. I must have kicked it or hit it while vacuuming or whatever. Cleaned the contacts and she's all better.
I've had the car since June 24th and this wiper problem and a rounded over flare nut on the fuel line into the Rochester carb while changing the fuel filter are the only problems so far.
Thank you Gene, Larry, Terry & Martin for your help.
Matt
I tried several paths, but finally had an extremely simple problem. The motor ground was good, and I had continuity through all the wires. (Terry - thanks for the schematics, they're utlimately what helped). I took apart the dash switch, it needed cleaning but was ok. The limit switch for the cowl being open was working fine. I even tried to pull the wiper motor to bench test it but the wiper transmission would not budge off the motor shaft, the nut came off fine but the linkage arm is frozen. I put that idea aside.
Going back to the schematic and saying OK power starts here - I found the yellow jumper wire in the front of fuse block was loose and not passing the voltage on. I must have kicked it or hit it while vacuuming or whatever. Cleaned the contacts and she's all better.
I've had the car since June 24th and this wiper problem and a rounded over flare nut on the fuel line into the Rochester carb while changing the fuel filter are the only problems so far.
Thank you Gene, Larry, Terry & Martin for your help.
Matt
