97 Tahoe W/ R-Defrost Ac Panel Issue

[TTZ06]

Hopefully my post will help some others as y'all help me to find what is wrong.

97Tahoe W rear defrost.
Symptoms:
Ac does not come on
Blower motor as of today only works on high, has not worked at all before.
Only the defrost seems to work and only on the pass side does it blow any air. It will not switch modes

I pulled out the panel to notice 2 wires severely corroded. One looks blue and the other black?? My eyesight is poor so I might have the colors wrong. Here is a pic of it.

What voltage should I be reading at these two wires, if any, so I know what I am looking for and at.

Thanks

Jerry

 

[SunlitComet]

That brown(black) is the power supply to the whole thing. The Light blue(blue) feeds 12volts to the resistor block and is second highest speed now as medium 2(medium-high). That power wire only has enogh capacity at the moment to activavte the high relay any other setting will be very weak or non functional. get your self a new pigtail.


Front HVAC Blower Motor
Heating and Ventilation

Notes

Heater Blower Controls Schematics: Front HVAC Blower Motor

---------- Post added at 12:18 PM ---------- Previous post was at 12:14 PM ----------

I believe pigtail is ACDelco pt1346.

 

[TTZ06]

Is that pigtail something I can pick up at an auto parts store?

Further investigation showed the following

I believe this is the blower motor switch. The top left element is burned.

I was reading about a resistor so I went looking for one. I found this instead.

The best I can tell it runs into this relay

 

[SunlitComet]

I believe that red one is from blower fuse in underhood fuse block. power supply for relay for high speed. Believe the others to be grounds.

---------- Post added at 01:27 PM ---------- Previous post was at 01:24 PM ----------

or is that more purple?

 

[TTZ06]

Cool deal. I repaired that harness, Now I need to repair the pigtail the get a new blower control switch and see how that works.

Thanks for all the help. You truly are an asset to this forum.

---------- Post added at 03:28 PM ---------- Previous post was at 03:28 PM ----------

They both look black to me

---------- Post added at 03:31 PM ---------- Previous post was at 03:28 PM ----------

Unless you meant the red one then yes, it is red

 

[SunlitComet]

that pt1346 should be the one. The wire are not color coded tho. that is just a detail.

 

[TTZ06]

Well I replaced the blower switch and repaired all the wires. The fan works on all speeds now, but the AC still does not come on. I will hook a set of gauges up next to make sure its not empty ( hence the reason it wont turn on )

 

[SunlitComet]

There is actually a lot of things that can kill it but yeah try pressure readings first.