91 Z28, 305. Every time I turn on the heat/blower motor the car wants to die, all the lights dim, and so on. The car will actually stall. I imagine the blower motor is drawing too many amps and have decided to try and replace the blower motor resistor. Unfortunately, this is my first encounter with a blower motor resistor on this car and Im not exactly sure where the thing is. Being a Mercedes mechanic, I know not to touch when in doubt, so Im hoping I can get a good location for the blower motor resistor from you guys before I go tearing things apart. Hope to hear from someone soon. Any tips on it would be excellent too.
Thanx,
Chris

 

Being a mechanic I am going to assume your sure its not your alternator. The reason I say is I had a similar problem and my guage (voltage gauge)was fine, but when tested was only putting out 13volts, which isn't bad, except in the winter when the heater,radio,rear defroster,headlights,etc. were all on. Also, if i am not mistaken, the blower motor resistor, when bad, will make it so only high works on fan speed.

 

Here's a pic, but I think you're barking up the wrong tree:

https://www.thirdgen.org/forums/cool...er-heater.html

More info:

https://www.thirdgen.org/forums/elec...lower+resistor

JamesC

 

If your fan works in all speeds then your blower motor and resistor pack are functioning properly. If your vehicle stalls when adding an electrical load then you have a charging system fault. Check these things first before you go throwing parts at it.
1. Disconnect both terminals at the battery and look for signs of corrosion where the terminal touches the battery. If corroded, or if the threads on the bolt look worn then replace the terminal bolts and clean the terminal rings with a small sharp knife. Retighten the terminal connections but do not overtighten them and strip out the threads on your battery! The terminals should be too tight to turn by hand. If you can move them with your hand they are not tight enough. If they will not tighten any more then they are stripped and you will need a new battery.
2. Have the battery load tested at Auto Zone, O'Reilly's or Advance. Load test it not just connect a voltmeter. It is possible to have a weak cell in the battery causing the problem.
3. While at the auto parts store have them load test the alternator as well. With no load on the car it should put out no less than 13.0 volts. with a full load (heater fan on high, wiper motors going full speed, headlights on, radio on, rear defroster etc you get the idea) it should be no less than 12.5.
Let me know if this helps.
Mike