Tonight I had the fun task of replacing my ignition switch and connector on my 89 Cherokee. Fun because I had to do it in sub-zero temps in my driveway! The brown wire was cooked. Since I don't want to do this again any time soon, can anyone tell me what causes this condition? Is it the switch itself or another issue (bad grounds etc?) I seem to recall someone saying the blower motor causes an excessive draw and can cause the issue. Is this true?
Thanks!
BTW- these switches are still available at Chrysler.

Todd

 

See what others say...Any poor connection can make heat that does not help the connection. Then it snowballs to that hot thing boogers the switch.

Yes, I have seen an old blower, (E-fan), work fine and draw nutty current. No doubt a heater fan could do that. Probably windings shorting. In my case it would blow the fuse, but it ran great with direct power.

 

X2 on bad connections causing heat and smoking the wiring....
High current draw is of course another culprit...
My blower switch was fried, along with it's connector, but the ignition switch was OK. Seems that the blower switches are built too light to stand a bad blower motor for very long....

 

My (pre91) does not have a blower relay, meaning it's current goes through the ign switch. I think any connection handling that relatively high current could fail/snowball...Including Bill's blower switch.

The cheapo-chinese meters will measure up to 10 amps. A little more gets you to 20 amps. I don't know the draw of a blower on high. Heck, put a 10 Amp fuse in there for the blower and see what happens?.....

Or an amp meter. Pull the fuse and put the power trough it, see what it's drawing.

 

Crappy switches. They had the same issues in GM vehicles.

Refresh all grounds and connections to minimize the resistance in the circuit. Blower motor ground, wiper ground, turn signal ground.......

Ever done Tips 1, 3, 4, and 5?