Reconstituting missing wiring
Posted: Mon Dec 26, 2016 12:01 am
Problem: my '78 Westy is missing the harness for the booster fan.
Description: The relay is still there, as well as the connector coming out of the motor. Below, I found a red wire, with half of an inline fuse holder, which I assume it should go to prong M on the relay. Next to the red wire there is an inch of brown/white wire sticking out of the harness, which I think it's the tracer to the heat lever switch in the dash, and should go to #31 on the relay. I know I have to hook up a yellow/white wire from the fan motor connector to 8 and jump it to J, and then somehow ground the other side of the motor connector. Lastly, run two black wires: one from relay prong A to #15 on the ignition coil, and one from the same prong A to the ignition switch.
I have four questions:
1. where to ground the fan motor?
2. why connect the relay to the ignition coil? I assume that the ignition coil will energize the relay coil (and the dash switch will close the ground side of the circuit). But so will the ignition switch, so it's like having two hot wires on the same prong?
3. I can't locate the black wire coming from the ignition switch. Where should I look?
4. Until I get my hands on original wiring, I am planning to attempt reconstruction using a generic Bosch type 4 prong relay+harness, and generic inline fuse holder. I will substitute as follows: A=86; M=30; J,8=87; 31=85. Are there any caveats I should be aware of? Some pictures of the original 1978 wire setup, if available, would be really appreciated.
Thank you
Description: The relay is still there, as well as the connector coming out of the motor. Below, I found a red wire, with half of an inline fuse holder, which I assume it should go to prong M on the relay. Next to the red wire there is an inch of brown/white wire sticking out of the harness, which I think it's the tracer to the heat lever switch in the dash, and should go to #31 on the relay. I know I have to hook up a yellow/white wire from the fan motor connector to 8 and jump it to J, and then somehow ground the other side of the motor connector. Lastly, run two black wires: one from relay prong A to #15 on the ignition coil, and one from the same prong A to the ignition switch.
I have four questions:
1. where to ground the fan motor?
2. why connect the relay to the ignition coil? I assume that the ignition coil will energize the relay coil (and the dash switch will close the ground side of the circuit). But so will the ignition switch, so it's like having two hot wires on the same prong?
3. I can't locate the black wire coming from the ignition switch. Where should I look?
4. Until I get my hands on original wiring, I am planning to attempt reconstruction using a generic Bosch type 4 prong relay+harness, and generic inline fuse holder. I will substitute as follows: A=86; M=30; J,8=87; 31=85. Are there any caveats I should be aware of? Some pictures of the original 1978 wire setup, if available, would be really appreciated.
Thank you