Need some help with my A/C PLEASE

[Bigred81]

I’ve got a 99 suburban. On a 3 year project I have replaced every part and line of my ac. Long story. Learned to never buy a compressor at a good deal because it might implode and fill your entire system with aluminum shavings, anyways everything is new and I got it charged. It works. I turned the fan control to high and nothing and smelled electrical. Took out hvac controls and found some melted plastic. Went to the junk yard. Found hvac controls that are like new and no tabs broken and wiring harness. Replaced plug, soldered the wires replaced hvac controls and turned it to high and nothing. All other speeds work. I believe I’ve got too my draw on the fan setting when turned to “high” as you can see in the pictures. Any ideas guy? I’m an idiot when I comes to electrical. Other than the high fan speed giving me issues with two setups it works great. I have a daughter with epilepsy and her sweat glands don’t work, because of meds so I need some cold air. I would greatly appreciate any help.

You must be registered for see images attach

You must be registered for see images attach

 

[kennythewelder]

Have you replaced your resistor? This is on top of the evap core box. Most of the time, if your blower wont work on 1 or more speeds, but works on other speeds, its the resistor.

xc_hide_links_from_guests_guests_error_hide_media

xc_hide_links_from_guests_guests_error_hide_media

 

[AK49BWL]

The high fan output of the switch goes to a relay to activate high speed, so you'll want to check that relay.

The wire that burned up was brown, right? That's the ignition feed, not the output to the relay. Yeah you have too much current through the switch, which for these trucks is pretty typical..But it won't be in the high speed position. You might need a new blower fan, as it might be coming to its end of life and drawing more current than it should.

The other slightly burnt pin in the switch (top left in the pic) is speed 3.. That and the ignition feed are the two I always see burnt in these switches.

 

[Bigred81]

The high fan output of the switch goes to a relay to activate high speed, so you'll want to check that relay.

The wire that burned up was brown, right? That's the ignition feed, not the output to the relay. Yeah you have too much current through the switch, which for these trucks is pretty typical..But it won't be in the high speed position. You might need a new blower fan, as it might be coming to its end of life and drawing more current than it should.

The other slightly burnt pin in the switch (top left in the pic) is speed 3.. That and the ignition feed are the two I always see burnt in these switches.

 

[Bigred81]

The blower and resister are new. I replaced them along with the hvac doors when I replaced the condenser. Since posting this my ac no longer works. Just got air and the compressor won’t engage. I switched the relay under the hood with the started relay to do a quick check and both are working so it’s not the relay. It’s also not the fuse on the driver side dash panel or the fuse under the hood. Is the resistor under the hood the one you recommended I check or is there another one? And yes it’s the brown wire the melted. This is frustrating. I’ve spent over $1,000 in this ac using ac ACDelco parts.

 

[Bigred81]

The blower and resister are new. I replaced them along with the hvac doors when I replaced the condenser. Since posting this my ac no longer works. Just got air and the compressor won’t engage. I switched the relay under the hood with the started relay to do a quick check and both are working so it’s not the relay. It’s also not the fuse on the driver side dash panel or the fuse under the hood. Is the resistor under the hood the one you recommended I check or is there another one? And yes it’s the brown wire the melted. This is frustrating. I’ve spent over $1,000 in this ac using ac ACDelco parts.

I’m kind of wondering about a ground somewhere. Is that possible? I did remove the dash to replace ac parts. Could have don’t it then. I did put a 2” body lift on. Could of done it then. I just can’t find where the ground for the ac is at. If I remember correctly the ac always has power and the button just provides the ground.

 

[SUBURBAN5]

Thought the resistors were under the airbag next to 3relays? Also I'm just chiming in. You said the control panel new right? Ac delco?

 

[Bigred81]

Thought the resistors were under the airbag next to 3relays? Also I'm just chiming in. You said the control panel new right? Ac delco?

I just pulled the control panel from the junk yard. It looks to be under 5 years old so I’m assuming previous car owner replaced it. It was working fine. I’m basically having the same problem after replacing the controls. I just used a power probe and jumped the compressor on and it works. There is something somewhere that is causing problems in a few locations with my ac. AC button doesn’t work after using it for 30 minutes. Just like my previous HVAC controls. You said the resistor next to 3 relays by the airbag. Are you talking about the resistor on the top of HVAC box on the passenger side under the dash? I did replace that but buying another one. I’ve replaced new parts and had them be faulty. I didn’t think that would affect my compressor. But maybe so.

 

[SUBURBAN5]

I don't think those relays control the compressor , i thought they had to do with fan speed. When I would run mine I could hear a click. Dont quote me at it though. I've just also redid my ac and replaced a crap load of parts so just going down the list with you with what I did

 

[SUBURBAN5]

Also you made sure you got the controls that are an exact match. There's 2 type of ac control modules for that style