A/C control

[matuva]

Good day all,

any of you have knowledge to share about A/C control system?

It happens suddenly, fan speed from Low, 1, 2, 3 did quit.
Only High speed is left.

We put a brand new ACDelco A/C controler, no change. We even put a new blower motor, no change too.
I haven't found the electric diagram for that system, and I confess
I have few knowledge in this kind of electrical devices...

 

[3500GMC]

Blower motor resistor, or associated connections..

 

[WarWagon]

Resisters are the place to look.

What year you playing with? Just about all GM trucks melt connectors down. 95 era is a 2 wire plug behind the glovebox for the HVAC system. The 2005 era melts the connector down at the blower resister and is covered under an extended silent warranty. 10 year or 150K miles.

 

[matuva]

That's on a 1997 K1500.

How do these resistor look like?

 

[matuva]

I found these pics in a catalog. Is it what I have to look at "behind" the glove box??



Where is this electronic board located?

 

[ak diesel driver]

top 2 are the same just opposite sides. it is what your looking for. It is in the ductwork close to the fan on the top IIRC. tight fit as well, hard to get it in/out without bending the resistor springs

 

[JMJNet]

Chances are you need to change the blower resistor.

Behind glovebox on top of the blower housing as AK indicated.

I am not sure where the third picture comes from but I don't think you have to worry about that.

 

[saratoga]

Moved to electrical.

 

[3500GMC]

Often the new resistor will get burnt out too, then once the blower motor is replaced, ..and you buy a second new replacement resistor,.. all is well.

 

[matuva]

it took a while after I pulled the glove box to finally find where is sitting the beast :



Then, after I succeed in pulling the 2 tiny bolts ( thanks to the GM engineer who designed that ), I tried with no luck to pull it out to replace it with another one coming from a 1995 truck.
The 1995 donor truck has no passenger airbag, and it was a true PITA to pull the part out, but on the 1997 truck, with the bottom of the passenger airbag (see arrows), IMO it is virtually impossible to change this part without parting out the dashboard.



I finally gave up... It will continue using the Highest speed fan, at least I can find how to extract the old part...

 

[ak diesel driver]

on my 96 I ended up bending the arms that hold the springs (on purpose) and then straightening them before I put the screws in. Once you get it in there's actually a little room to maneuver.

 

[matuva]

Finally changed the resistors, but no luck...

 

[dangerousdave]

I don't want to derail this train, but I have lost the slow fan speed on my 94.
Probably the resistor?

I'm SURE there's a thread on this in here already, and I'm too lazy to look.

 

[matuva]

Bump?