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Discussion Starter #1
Anyone know where the heater/blowe motor realy is located on 1994 k2500 4x4. My heater fan only works on high, so i assume it is the relay...am i on the right track?

bundy :confused:
 

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To me, it sounds like it is either a wiring issue or the resistor block or maybe a fuse? I can't remember how the fuse setup is for this. The only relay I know of for the blower motor is the high blower motor relay. When that relay goes out you should have every speed except high.
 

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Discussion Starter #3
thanks, the fuses all appear good, checked them last night. where is the resistor located? behind glove box?
 

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Mine did the same and it was the blower relay. You should find it behind the glove box. If you have the new one you will see how the old one is bolted. Very small place.
 

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Well one way to test to make sure it is actually the relay is to do the following (for years 95+):
  1. Grab a DMM to measure voltage.
  2. Measure voltage at the purple wire (at blower motor). On high the voltage should be system voltage and the other three speeds the voltage should vary.
  3. If all voltages are fine, blower motor is most likely bad.
  4. If no voltage is on the lower three speeds or the high speed you will need to remove the high blower motor relay (located behind glovebox).
  5. For testing voltage for the lower speeds, Check the dark blue wire pin. If voltage is present go to step 11. If no voltage is present go to step 8
  6. For testing voltage for the high speed, Check the red wire. If no voltage is present, go to step 7.
  7. Check the one connector around the blower motor (has black and red wires) and make sure it is not melted. Then check the 50A under hood fuse. If everything checks out, Go to step 12.
  8. Check your 25A Heater/AC fuse. If fuse is ok, proceed to next step.
  9. Check voltages at the blower resistor (to make sure the switch itself isn't bad).
    1. Yellow wire is Lo Speed
    2. Tan wire is Med-Lo Speed
    3. Light Blue wire is Med-Hi Speed
  10. If you have voltage on all three wires with the switch in the correct spot for each wire (and key on) then most likely the blower resistor is bad.
  11. Replace High Blower Relay.
  12. With key on, turn fan speed switch to HI. Check the orange wire at high blower relay. Should have system voltage, if you do and the high speed did not work, the relay is bad.
I think that should help.... Hopefully it isn't to confusing and hopefully i got everything written down correctly lol.
 

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Sorry to bring this back up, but wanted to check and see if I should use the same procedure to check a non-fucntional blower. The underhood and dash fuses are good, rear blower works fine (its a 99 Suburban 1500) so I have heat to the interior. Just need the defroster, etc.

Going to go through and clean the grounds as well, lost the turn signals today! Hope that one is the grounds or the trailer connection.

Thanks in advance.

Ken
 
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