Heater/Defroster switch

[Guest tomw51]

Getting no power to heater/defroster switch. Was heater switch. The defroster has a loop with fuse running the the heater switch, good fuse but no power. I tested defroster and it hot wired good. Need a diagram so solve this problem. Could this be tied into the circuit breaker? Is circuit breaker inside under the dash ?

[peecher]

Had a similar prblem with my '48. There are two "hot" lines with fuses that feed the defroster and heater switches. They are located on the lower lip of the dash directly above the switch panel. I too couldn't get any power thru the heater feed so I ran a new wire with a fuse from the hot side of the circuit breaker to the heater switch. The circuit breaker is on the inside firewall above and to the right of the steering column. Unlike modern cars the accessories were not wired thru the ignition switch.

[Guest tomw51]

For the two Hot fused lines for the Heater and one for the Defroster, what size amp fuse should be used for each of the fuse links ? Currently I have only one line for both the heater and defroster and running a 20 amp fuse. I want to separate and make two separate lines.

[peecher]

The heater and defroster motors do not draw much current so the 20 amp is probably more than sufficent for the heaters and a 10 amp fuse for the defroster line should do it.

[Guest tomw51]

I find no second hot wire that works with the iginition, so I wonder if I could use the one Hot line in I have with a split from one wire to tow wires. Both wires with fuse links with one going to heater (20 amp line) and the other (10 amp line) to the defroster ? Is this okay ?

[peecher]

The heater and defroster feed lines do not go thru the ignition switch. If you are running new lines you can tap off the "hot" terminal on the circuit breaker. I don't think the ignition switch was intended ( or desined for) loads other than the ignition and power for the gauges.

If you use only one wire from the source and splice in the 2 separate heater and defroster that should work if the wire is heavy enough, maybe 14 or 12 gauge.

Edited December 27, 2010 by peecher (see edit history)