I have an electric fan and a thermo switch. When the temp gets to a point it turns on the fan. The switch also came with an override wire to connect to the AC clutch. I used this wire for a toggle switch on the dash. I installed vintage air and I want to run the clutch wire and toggle switch wire together to the override wire on the thermo switch. I'm wondering though, when the AC comes on if the clutch wire and toggle switch wire are tied together this will cause voltage to flow to the toggle switch and maybe burn it out? Also, if the clutch wire and toggle switch wire are tied together and I flip the toggle that will supply voltage to the clutch.

The only way I know to limit the direction of current flow is with a diode. Do they make those for an application such as this and should I use a couple? I guess I could use two power relays to accomplish this. Any other suggestions?

I picked up some heavy duty diodes from Radio Shack. I wired one on the toggle switch and one from the compressor wire and tied everything together. Everything seems to be working fine. graemlins/thumbsup.gif

One of the most important things to consider with diodes is the power dissipation factor. Most garden variety diodes are 1 watt. If you assume the diode drops 0.7V (it's probably 0.6v), then the power dissipation at 10 amps will be 7 watts. That will require a bigger diode that can be mounted to a heat sink.

It all depends on the rating of the diode and current through it. If you exceed the wattage rating, it's only a matter of time until it burns out. Just multiply your current load by 0.7 and see what you get.

-dnult

I'll check what it is. The manager said it was the biggest diode they had and was rated for something like 50 volts??? I'll check the specs, because "volts" doesn't sound right.....should be amps.


50 volts, 6 amps is what they are rated for....