Heater/a-c

[StoneyPgh]

Just got back from the dealer about two heater problems I have on my

'03 Chevy 2500HD. When the service writer informed me that I would

be charged $90 just to have it "diagnosed", I told him, "No thanks".

 

First problem: the blower does not work on highest speed (#5), but

it works fine on all the lower speeds (# 1 thru #4).

 

Second problem: temperature bar (red-blue) on the right side does

not light up, but the one on the left does.

 

If I had a little insight as to what to look for, or replace, I'm sure I could

make the repairs myself, hopefully for less than the $90 diagnostic charge.

[Import Hater]

First problem sounds like a blower motor resistor.

 

Second probelms sounds like a burned out bulb (which is not available seperately through GM parts) in the HVAC control head.

[StoneyPgh]

First problem sounds like a blower motor resistor.

I thought there was no resistor on the highest fan speed (#5). Am I wrong?

[Import Hater]

There is a 5 terminal relay that is part of the blower motor resistor assembly that bypasses all the resistors when switched to hi blower speed. Most likely this relay is stuck.

[StoneyPgh]

If that's the way the relay works, then it's likely to be the problem.

 

Any idea where it's hiding?

[Import Hater]

From what I see on the schematic, it's part of the blower motor resistor assembly. So it's integrated to the resistor.

 

Also looking at the schematic...it looks like high speed gets power from another feed. When you switch to high blower, the relay energizes, and switches the power circuit to the fan to bypass the resistor(s). Check the 40amp BLOWER fuse in the underhood fuse box before rushing out and buying a resistor. If the fuse is OK, then you've probably got a stuck relay.

 

The relay is right next to the blower motor. You'll have to take off the kickpanel shield over the HVAC module to get access it.

[atboley]

check the connector at the resistor really good to... most of the time when high speed goes out it because the terminal overheated and burnt and melted and is not making contact anymore... you may have to replace the resistor and the connector...