Repairing The Wiper Door Selenoid

The wiper door selenoid is located on the back of the tachometer. It's mounted with two screws near the bottom right side of the tach. The problem with these units is that they get dirty from years of use. This causes the double sided needle valve inside to stop functioning. When the unit doesn't function, the wiper door will not open by using the wiper switch. It will open if the override switch under the dash is used.

This is what the unit looks like:

To clean the unit:

1. Drill out the two rivits shown in the picture with a 1/8" drill. Be careful as there isn't much meat on the cylinder portion and you will need to use these 1/8" holes for re-assembly.

2. Disassemble the unit. You should have a flange plate, cylindrical housing, winding, metal nipple, spring, and needle. These parts are shown here:

3. Clean the parts as good as possible. I used mineral spirits but am sure that other products will work juat as well. It's especially important that the needle ends and seats are cleaned. Use a Q-tip to clean deep inside the needle housing as it will be full of dirt and contains a seat. The other seat is on the metal nipple.

4.Re-assemble the unit as it was taken apart. Use 1/8" pop rivits to hold the housing together. Re-install on the back of the tach and hook up the hoses and wires.

5. Watch your wiper door FINALLY work with a touch of the switch!