I'm rewiring my Mk I. The car has the 2sp fan switch (with the ceramic(?) block by lugs 7 & 8). The CAT wiring diagram shows a green wire and a brown wire from the switch (lugs 6 & 8 IIRC) "leaving" the switch. It shows only a single wire (and GND) on the motor. I have seen a "big green resistor" mentioned in other readings. Do I need this resistor in series with either the green or brown wire, then both of those attach to the one motor input wire? The resistor is not shown on the CAT schematic. A PO had been inside the dash long, long ago, so everything is not necessarily original..... I would like to take advantage of the 2sp fan, but it not practical, I can live with a single speed.
Big green resistor? heater fan wiring question
- Thread starter KLtiger
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KL, have a resistor if you want to try it
Austin Healer
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I'll draw up the schematic in the morning. I have tons of the resistors. The mk1 with a single speed fan used a simple switch on the fan control slider in the center of the dash and did not have a fan switch at the extreme left (LHD cars) of the dashboard. To use the 2 speed fan, you need to have the correct switch on the dash face (extreme LH hole above the padded roll) and the resistor. The fan switch is the same as the wiper and headlight switch. I have gobs of these as well, but they are also readily available from Moss and others... They are common with the Austin Healey 3000 Mk3 headlight switch...
In any event, I'd be happy to supply the switch, resistor and wiring diagram!
The entire system is extremely easy to retrofit!
If you would send me the wiring diagram, that would be perfect--thanks. That is what I need. The control slider switch, which I think should have been in my car originally, had been replaced by the PO. The resistor in it had no doubt failed and he replaced it with the later control lever and the 2sp switch--but, no green resistor. I've got a fan (toggle) switch that I know is correct. And, Kragh is nearby, so I'll get the resistor from him. Thank you!
Austin Healer
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the resistor is riveted to the bracket for the heater fan. there is/was a 2 wire harness attached to the resistor. one side of the resistor is soldered to the hi speed feed wire to the switch AND the feed wire to the fan motor. the other side of the resistor is the slow speed feed to the switch. connections at the switch are Term #1 green power feed, term #4 Low speed feed wire, term #8 hi speed feed wire. If the resistor that Kragh has does not have the sub-harness soldered to it, I can supply one.
I'll dig out a fan in a little bit and take pictures of how the resistor is mounted and what the sub-harness looks like
I'll dig out a fan in a little bit and take pictures of how the resistor is mounted and what the sub-harness looks like
Austin Healer
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as promised, here are some pics of the mounting method and wiring sub-harness
