I was replacing the burned coils on my heater/ac fan resistor block. I was wondering if anyone had one in good shape that they could check the resistance values on. I need the resistance to figure the length of nichrome wire coils to replace them with. The coils on mine are broke and corroded so I can't get a good reading of the resistances.

JM:

 

I've thought about repairing the OEM units, but I doubt they would hold up long. The heat from the soldering iron will further deteriorate the element.

 

Awhile back Bill Putney (I think that's his name) posted a schematic he drew up for a resister block using common components available places like Radio Shack. You might want to try a search. Not sure if the old stuff was moved to this new web page.

 

As I recall, his plans called for high tolerance resisters, which were next to impossible to burn up. The downside was that the block was physically larger, and would not fit in the usual spot.

 

Good luck, John

I just did exactly what Jelly Man is considering, replacing the burnt out coils with new nichrome wire. Each of the coils is around 1 ohm. I think I measured the originals around 0.8, 1.2 and 1.3 ohms from thickest wire to thinist (some were thrashed though, so that may not be what they originally were when new).

The two smallest wires on mine were broken and I just replaced them both with 1.2ohm coils, which gave a decent range of fan speeds.. Anything from 0.8 to 1.4 would probably be fine.

Nichrome doesn't solder very well, so it's a good idea to put a bit of a bend in the end of the wire and then 'encase' it in the solder puddle so even if the bond isn't great it won't fall out.

I have access to a silver solder tool. Just gotta find some of this nichrome wire...Anyone have a source?

http://www.omega.com/pptst/NI80.html

 

The higher resistance/foot the less you'll need, but the thinner stuff is hard to work with (doesn't hold it's coil shape and is more delicate).

 

Or you could dig it out of an old toaster, space heater etc. Pretty much the same stuff, you just need the right resistance.

I’ve successfully salvaged nichrome wire out of hair dryers, better to crimp it with a physical connection than solder it if you can.

 

 

I fixed my blower coils by just twisting them back together at the break, not the best permanent solution but its worked for about 4 months.

 

 

Gary

My windshield leaked rainwater down into the A/C duct. This ruined the blower motor (rusted the bearings) and of course killed the resistor block. I was gonna go hi-tek and install a PWM DC motor controller, such that it would have infinite speed control on the fan. But I cheaped out and found a used resistor block on Ebay for a few bucks, and all is good again.