1968 rr electrical problems

[Phils68RR]

Hi got a 68 rr, full restoration, cannot get the heater motor to work or dome light, have power to the dome light and heater motor wires, dome light will not come on, and heater motor will not come on, the things that work are the map light, headlights, tail lights marker lights, windshield wipers, starter so far. Thanks phil

 

[Yatzee]

Use the diagram from my previous post to get the wire color codes. Remove the heater resistor and check for burnt coils on the back side. Temporarily hot wire the heater motor to see if it runs at all but be sure to use an inline 15amp fuse in case it's dead shorted. Inspect the resistor block for broken coils and corroded contacts. Power comes in on the BLK=TR wire from the fuse box to the heater switch and goes to the blower via Red/ Lite Green and Dark Green. With the ignition on and the fuse good, probe the connector that goes to the resistor as you change fan speeds at the dash. If you have nothing in voltage, it's either the heater switch or the problem is back at the fuse box. If you do have power at these terminals the problem is either a faulty resistor card or the motor.
For the dome light, 12v+ goes to the light under the headliner and the door switches make ground to complete the circuit. Unscrew and extract your door switches slowly to make sure the wires inside the door pillars are actually attached and clean for they have to make ground. If this is the case, check the fuse, and if it's OK then you can assume the power feed to the headlight switch is OK. The headlight switch also serves the purpose of turning on the dome light when all the doors ar closed by rotating the knob so this is one item that may be at fault specifically the wrapped wire resistor on the front of the switch and the sliding contact strip. You will see these once the switch is removed. As you slowly advance the knob clockwise the dash lights get brighter but when you hit the end of the knobs rotation contacts are made and the dome light comes on. Most probably your headlight switch is bad and needs replacing. There are other factors present so using the wire diagram you can probe for power and grounds at your leisure.

 

[Phils68RR]

thanks for the help, dont have the door switchs in yet, trouble shooting th heater now thaanks again Phil from Corpus Christi

 

[jimt1971rr]

Do you have a Factory Service Manual? I found the wiring schematics invaluable when doing the electrical on my 71.

 

[mmissile]

Grounds?