[Rich-L79]

Okay, this is the wiper motor on the truck, but I use the truck to haul the Chevelle (just to keep this Chevelle related).

1. the switch: 10 ohms between the terminals when the switches are on. No problem.

2. the motor: 10 ohms between all the terminals that power the motor and 10 ohms between the terminals on the washer pump. No problem.

3. the wiring: 10 ohms from switch-end wire terminals to motor-end wire terminals (light blue to light blue, dark blue to dark blue and black to black). No problem.

4. the wiper arm mechanism: all free moving with no binding. Even with the mechanism disconnected the same problems (see below) exist.

Problem: when I turn on the switch the motor won't move. The fuse is not blown. If I turn on the wipers to high (two-speed) and help them get started by hand they barely keep moving and usually stop after a few wipes. The low setting will not move them at all. Pushing the washer motor switch while turning on the motor switch will usually get them moving by themselves but they stop when the washer stops.

The motor is rebuilt-new about a year and a half ago. It's been getting steadily weaker. I hooked the motor up directly to the battery and it ran for a few turns and then stopped. No more direct current would get it started again even with a push. I can still get a ohms reading through the terminals.

The motor is also fed with yellow wires which I have not traced to check their continuity and they don't go to the switch. Everything has a good ground.

What am I missing? What could be causing the problem?


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[John_Muha]

Rich
What year truck. Offhand the weak movement sound like motor or the transmission is binding up.

 

[Rich-L79]

The truck is a 1969 Chevy C10 (half ton). The wiper motor looks a whole lot like the rectangular-bodied motors used on Chevelles.

 

[John_Muha]

Yellow is a switched 12 volt line. It is switched from the ignition switch and not from the wiper switch. The other wires are all switched to ground through the wiper switch. Check this thread out. It has some explanations and a link to the showroom pictures. If the motor is trying to work and just doesn't have any torque, sounds like a motor problem. http://www.chevelles.com/forum/Forum22/HTML/001500.html

 

[Rich-L79]

How many amps should I see at the motor with the switch on low and with the switch on high? I'd like to check that the proper amount of juice is reaching motor. When I replaced the old motor about a year ago this was the same problem I was addressing then. I suppose I could have gotten a bad one which seems likely since it won't even run with a full 12 volts from the battery.

 

[John_Muha]

Don't know the current draw on that motor. Never had a need to measure one. However, if your concern is the motor isn't getting enough, I wouldn't worry about that. If you hook up the wiper motor to the battery (like you did) the motor is going to draw as much current as it wants to. A good battery can deliver more than the motor wants.

 

[Rich-L79]

I'll assume it is a bad wiper motor unless I can find a problem with the switch. I tested it off the truck but I suppose I should reinstall it and check that it grounds well, etc.