Blower Motor & Stuff

Hello,
Still having trouble with the heat. The low and mid range blower motor speeds stopped working, which left only high speed. Then it began to stop and start - then stopped working all together. I am familiar with the blower motor resistor and the high speed relay - both of which I replaced. However I noticed something as follows:

On the connector for the high speed relay, where the purple wire exits (and goes to the blower motor), the connector was a bit melted and deformed (at that pin only). Then on the connector for the blower motor resistor, where the blue wire exits the connector and goes to the high speed relay, that part of the connector was also a bit melted and deformed (which explained why there was no low and mid speeds). I did test the other wires in the resistor connector to see that they were getting power corresponding to the controls in the van - all worked fine.

I am assuming that too much voltage passing through these particular wires/connectors would have caused that. Am I on the right track? If so, what caused that to happen?

I really appreciate all of you and the advice you have given.
Roland

I suspect your lumina is the 1990-1995 vintage, hence the high speed relay is in the engine compartment.
THis relay contacts pass both the high speed and lower speeds. SO if contact 30/purple wire is fried, it is fried for all speeds....(see diagram below) .
Long operation at the higher speeds eventually melts the relay and sockets contacts because the high speed burns about 25 AMps....which eventually also fries the blower motor. I have suggested many times that the higher speed should be reserved for short bursts only because obviously, the components are not able to sustain such a high current for long periods of time...and this applies also to a lot of other cars.
So....keep paying attention to the high speed relay, wiring and socket. THe problem is most probably there.
http://www.avigex.ca/xport/hvac_diagram_front.jpg

edit: ahh ok...found in another post you have a 1995-3.8...

I suspect your lumina is the 1990-1995 vintage, hence the high speed relay is in the engine compartment.
THis relay contacts pass both the high speed and lower speeds. SO if contact 30/purple wire is fried, it is fried for all speeds....(see diagram below) .
Long operation at the higher speeds eventually melts the relay and sockets contacts because the high speed burns about 25 AMps....which eventually also fries the blower motor. I have suggested many times that the higher speed should be reserved for short bursts only because obviously, the components are not able to sustain such a high current for long periods of time...and this applies also to a lot of other cars.
So....keep paying attention to the high speed relay, wiring and socket. THe problem is most probably there.
http://www.avigex.ca/xport/hvac_diagram_front.jpg

edit: ahh ok...found in another post you have a 1995-3.8...

Yep- I have read your suggestion to use the hi-speed only in short bursts. Even when the low and mid speeds quit working, I only used the hi-speed for short bursts. I understand what you said about the purple wire, but what about:

"Then on the connector for the blower motor resistor, where the blue wire exits the connector and goes to the high speed relay, that part of the connector was also a bit melted and deformed."

Any idea why this pin where the blue wire comes out would also be a bit melted and deformed? It seems to me that all speeds except high send power to the relay through this blue wire.
Thanks again!
Roland

... on the connector for the blower motor resistor, where the blue wire exits the connector and goes to the high speed relay, that part of the connector was also a bit melted and deformed."

Well....technically, it could suggest that the resistor section between B and A has shorted, (unlikely though...but...as Mythbusters might say,....possible) transforming that medium-high M2 speed to full high speed with same consequences..... Do you have any hint that the M2 speed could have become higher than expected..?

...or...the resistor between A and B, being a resistor, develops heat when it carries current...and that heat can reach connectors and eventually cause heat damage. NOtice that a damaged motor will draw excessive current and would overload the resistor pack, leading into that kind of trouble... If you can connect directly from the battary to the blower motor, and hook an ammeter into the circuit, you should read no more than 25 amps with a normal motor with 12V at the motor. Use of small gauge wires can act as resistors and limit current and leave reduced voltage at the motor providing unconclusive results....

Resistor values for the resistor pack are very low, from a few ohms to a fraction of an ohm...not all ohmmeters can read these values with precision....GM does not tell of the actual values that sould be measured....

Well....technically, it could suggest that the resistor section between B and A has shorted, (unlikely though...but...as Mythbusters might say,....possible) transforming that medium-high M2 speed to full high speed with same consequences..... Do you have any hint that the M2 speed could have become higher than expected..?

...or...the resistor between A and B, being a resistor, develops heat when it carries current...and that heat can reach connectors and eventually cause heat damage. NOtice that a damaged motor will draw excessive current and would overload the resistor pack, leading into that kind of trouble... If you can connect directly from the battary to the blower motor, and hook an ammeter into the circuit, you should read no more than 25 amps with a normal motor with 12V at the motor. Use of small gauge wires can act as resistors and limit current and leave reduced voltage at the motor providing unconclusive results....

Resistor values for the resistor pack are very low, from a few ohms to a fraction of an ohm...not all ohmmeters can read these values with precision....GM does not tell of the actual values that sould be measured....


It is a brand new blower motor (I know these can occasionally be faulty), a brand new relay and brand new resistor. I did measure the voltage at the connector pins as I moved the controls inside the van from low to medium. All seemed in order. I plan to replace the connectors (both the relay and resistor) and hope for the best. I appreciate all of your knowledge and willingness to share. Muchos Kudos to you!
Roland