Another AC problem

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1998_K1500_Sub

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More info.
The water valve was replaced about two weeks ago. I never tested it for function but it is hooked up proper.

You may wish to check it for function, as that electro-mechanical vacuum switch may not be functioning correctly. If it's not supplying vacuum to the water valve, try blowing out the vacuum switch's vacuum passages with Brakleen. Obviously, you can independently test the water valve with a hand-held vacuum pump or other vacuum source.

The compressor had 6.5oz of Pag46 in it. I added 4.5oz Pag46 with UV dye throughout the system

Sounds acceptable. I would have done it a bit differently but that's water under the bridge.

On the top of my old dryer the sticker for suburban said 3lb 8oz so i had 5, 12oz cans of R134A and put 4 3/4 cans in. I don't remember the pressure readings but they were in the range for 70deg as was the temp outside.
Those dryers... when I bought a replacement ACDelco dryer for the Suburban it came with two or three stickers, each one showing different charge weights (4# was one weight, there were other weights). If your dryer was replaced at some prior time, the installer may have put the wrong sticker on it. Why would this happen? you ask. That same dryer was used on multiple, dual-AC GMT-400 vehicles over a range of years, and I believe I've actually read that in some years they used less than 4#. Go figure.

But I'm not going to tell you what you should do. I can tell you what the service manual says, and I can tell you that 4# is what I have in my 1998 K1500 L31 Suburban's system because the sticker on the old dryer, which I believe is original, said 4#.
 
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Spareparts

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Thanks for the help man!
The new pump does not have the switch but does have a place for one.
Think i will call an AC repair place and see what they will charge to put one in as i have no way to save the coolant.
The sticker on the old dryer said 3lb 8oz.
The new dryer came with no sticker.

As for the dome lights. I can't exactly say when they stopped working. I know when i got the truck they worked. Now they don't.
I know it sounds dumb but i never noticed they stopped working till a few weeks ago when i went camping.
My driveway is pretty well lit at home and where i park at work is also well lit up so they could have stopped working the day i got home with it or a few weeks ago when i went camping. Got this maybe last September so could be anytime between then and now.
The only thing i did when putting in the new radio was unplugged the old one and took it out.
When putting in the new aftermarket radio it was all plug and play using a premade adaptor harness. I did not cut any wires when installing the new radio and that is the only under dash work i have done.
 

1998_K1500_Sub

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As for the dome lights. I can't exactly say when they stopped working. I know when i got the truck they worked. Now they don't.

Here's a schematic for the interior lights. It's pretty simple, the lights are supplied with fused power and then grounded by either the headlight switch assy or the individual switches at each door.

There seems to be a common ground splice called S204, and a ground location G200. I've included for you the manual's description of their location. See the attached.

You might use your test light on one of the light fixtures and confirm that +12V is present on one of the bulb terminals. Too, you should find GND at the other bulb terminal when the any of the doors is open. Obviously one of these two is missing (power or GND) because the bulb would illuminate if both were present!
 

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Afiggis

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Welp, I give up, Electrical if NOT my strong suit by far and this proves it.
I can not figure out why the switch will not turn it on. I have replaced the CC switch panel. Swapped out the Relays under hood under dash.
Test light shows no power at the low pressure switch
Last thing i think i can try is a new (used)ECU
If i jump it at the Relay under the hood fuse box it works, Not as it should but it works and blows icy cold at 80deg outside.
Also replaced the Headlight switch and both front door switches and still no dome light when i open the door or move the dial all the way to the top.
They will come on if i press the switch on the dome lights themselves.
And yes all Fuses are good.
Following. Have a similar issue. Replacing my pcm did nothing. Was pondering doing climate control cluster as well but prefer to not just throw parts at the problem. Also not electrically inclined but have a buddy who is. Those schematics might help
 

Spareparts

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My switches were acting a little weird anyway like i had to push the ac button a few times before it would stay in and the heater speed was not acting right from high to medium.
The headlight switch was also acting a little strange.
For $30 i got what looks like a nearly new heater control panel from one truck and a newish headlight switch from another.
There was very little dust on/in them that would indicate years of use.
 

Spareparts

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Sorry, No i have not yet.
I did get a little diagnosing done though.
No lights will turn on when any door opens.
If i turn the rotary dimmer switch to the last position the two lower foot well light's and glove box light will illuminate but no other lights will come on. This is the same no matter where any other switch is tried.
That is as far as i have gotten to far. This Saturday or Sunday i will dig into it further.
 

Spareparts

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Well i have not got anything done on the dome lights but i did get these taillights installed after work last night.
I think they look nice.
Very well made. Solid construction and work perfect.
 

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Longshot379

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I did find this also but have not tried it yet.

"well here's the theory first

your PCM (powertrain control module) decides when and IF it wants the A/C compressor to run

when the PCM wants the compressor to operate it supplies a GROUND for the A/C relay

Therefore... FIRST let's see if the PCM is commanding the relay

the easiest way to remove the a/c relay
install a small wire to pin 85 of the relay...it SHOULD be marked on the relay
re-install the relay

they make cool little adapters for this but they cost about $100 off the tool truck

then using a regular test light, install one end to the vehicle battery and the other to that little ground wire

turn your a/c on, engine running obviously, and see if your test light illuminates

if it does not, then we have to repeat this same test but this time at the PCM pin # 1 connector #3

again, if no illumination then we need to find out why the PCM is not commanding the clutch operation

if however, it does not illuminate at the relay BUT lights at the PCM then you have an open in the circuit between the PCM and the a/c relay"
Which connector is connector 3 and how the wires numbered?
 
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