trying to get my wiper solonoid mounted on back of tach. to work. I have cleaned and replaced it. The two wires (one is a ground) and the other is a brown wire goes through the firewall to the wiper motor. On a wiring diagram that I bought shows that it goes to a wiring harness containing three wires that connects to the wiper motor (brown, red, and light blue). I know the wiper motor has been replaced in past with a typical GM wiper motor. What is the function of the BROWN wire? The wiper motor has the typical three wires for the motor and two wires for the washer pump. Thanks for any help!!!!!!!!

 

I'm not absolutely sure of the function of the brown wire. I believe it is simply to provide a signal to the selenoid (at the tach) so that the selenoid can be properly energized (or de-energized) depending on the condition existing at the motor. The selenoid only sends the signal to the wiper door to open or close. The wiper motor should function fine without it as long as the wiper door is open enough to let the system know it's not in the way (via the firewall switch).
What kind of problem is happening with your wipers? Is it just that the door won't open? Will it open with the override switch under the dash?

You say that the motor has been switched to a regular style unit. It's impossible to get the door opening / wipers wiping timed correctly unless you have the correct motor. There is an extra wire on the motor that attaches to the red wire coming from the firewall switch. That wire stops the motor if the door isn't open far enough to let the blades loose without nailing the door. You can still use the wipers with the wrong motor, you have to use the override switch to open the door and then the wiper swtich to make the motor go.

The wrong motor also does not have a provision for the ground needed for plastic cars. You can add one easy enough if it's missing and the motor doesn't run at all.

 

I just got my 68 wipers working this weekend. lbell101 is correct in that the brown wire provides current to the wiper solinoid, mounted on the tach, which causes the door to open. When the door is full open the switch on the firewall closes, providing a ground for the wiper via the override switch ( not the pull down plastic ****, but the rotary switch between the plastic *****).

I have a complete handdrawn schematic of the 68 wiper setup. If you want a copy let me know. I may have a 68 wiper motor for you also. Not the wiper assembly- just the correct motor. You would have to combine the two to have a complete 68 assembly.

There is also a good wiper paper in the tech section.

T :cheers:

 

Had the same problem went to napa and ordered a 68 motor they are a one year only set-up with the 3 wire plug .repaired mine with a vette vues magazine article dec 2001. Lets if this helps brown is vacuum motor control solenoid on tach housing .black is wiper door limit switch and also goes to dash service switch. red goes to the ignition switch and wiper fuse .On my new motor the wires were blk red white and connected to the 3 wire plug so white goes to blk and red goes to red and black goes to brown.Hope this helps.

 

Terry, I would love to have a copy of your wiring diagram. Can you send a copy to jreed@classicnw.com? Thanks!!!