Blower motor through a relay

Gotta love that wiring . . .
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Roycape
Posts: 32
Joined: Sat Jul 10, 2010 2:14 pm
Your car is a: 1981 Fiat Spider
Location: Toronto, Ont.

Blower motor through a relay

Post by Roycape »

All - I thought I had this figured out but I'm not clear now so I'll create a separate post from my other one. :?

After doing a little research, I believe that the resistor for the "Lo" voltage setting on a 1981 Spider is located in the blower motor itself. If that is the case, then I just need to add one relay before the blower switch. I will use the original power source to the heater switch to trigger the relay (pin 86 on the relay). This will the trigger the relay and provide direct power from the alternator to the switch and then the switch will provide power to the correct circuit in the motor for "Hi" or "Lo" speeds. This way I will bypass going through the ignition for direct power to the blower motor but still get high or low speeds through one relay.

Could someone confer with this or am I missing something? If not then I will have to use 2 relays for - one for the high speed and one for the low speed from the switch.

Again any input would be appreciated.
spider2081
Patron 2024
Patron 2024
Posts: 3015
Joined: Fri Jan 27, 2006 11:45 pm
Your car is a: 1981 Spider 2000
Location: Wallingford,CT

Re: Blower motor through a relay

Post by spider2081 »

Yes you can run the feed wire to the fan switch through a single relay.
The heater/defroster fan is not as high a current motor as many think. I measured the current drawn on a few fans, A decent working fan draws about 2.5 amps in the low position and 3.8 amps in the high position of the speed switch.
Roycape
Posts: 32
Joined: Sat Jul 10, 2010 2:14 pm
Your car is a: 1981 Fiat Spider
Location: Toronto, Ont.

Re: Blower motor through a relay

Post by Roycape »

Thanks Spider 2081. Much appreciated.
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