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Re: Time delay on AC cut-in after start

Posted: Mon Jul 15, 2019 12:11 pm
by grummin
That is about the same as my car is doing. I am also not in a huge hurry but it is annoying now that its reaching 100 here in central Texas already. The more I think about it I am thinking it is a compressor issue or the controller that controls the variable displacement. I will post in here if i figure it out.

Re: Time delay on AC cut-in after start

Posted: Mon Jul 15, 2019 4:48 pm
by s/c'd cav
9C1fanatic wrote: Tue Mar 08, 2016 1:08 am I have seen the opposite problem on both my new 14 caprice and my work 14 caprice. The compressor will sometimes run for several minutes even after you have turned the AC button off. I figured there is probably some rhyme or reason to this programming. I am going to assume the AC is probably controlled by a combination of the PCM and BCM.
mine will do that , if you push the recirc button , then back to fresh air it shuts off

Re: Time delay on AC cut-in after start

Posted: Fri Aug 13, 2021 1:41 pm
by aclynn
grummin wrote: Mon Jul 15, 2019 12:11 pm That is about the same as my car is doing. I am also not in a huge hurry but it is annoying now that its reaching 100 here in central Texas already. The more I think about it I am thinking it is a compressor issue or the controller that controls the variable displacement. I will post in here if i figure it out.
Its probably too late to let you know what the fix is but hopefully anyone else having the same issue will be able to find this. The issue is upon start up, ac compressor does not engage, takes several minutes before cold air is present. The problem is not the compressor or the controller. The problem is, Excessive heat under the hood causes fan relay damage and failure. There are 3 fan relays. Fan relay 2 if OEM is black, this is usually the failing relay. Checking the other two relays, if OEM they are gray, look for discoloration, if so replace them. Fan 1 is the relay that closest to the engine and gets the most heat. There are two service bulletins that address this problem, the first one from GM is Pl1069. This bulletin refers to No fan or fan continues after key is off but will show you examples of deflective relays. The second GM bulletin is 09-06-03-007A. This bulletin refers to Temperature gage reading HOT and intermittent Fan or inoperative fan. This bulletin is step by step to relocate the 3 relays from the fuse box to the radiator support (passenger side). It includes the part numbers for the additional wiring harness. It says 1.5 hours labor to splice those wires and move the relays.

Re: Time delay on AC cut-in after start

Posted: Mon Aug 16, 2021 11:25 am
by elc32955
Hmmmm.... fans slow to kick in due to burnt relays. Very interesting, thanks for posting this info up. I'll have to check my fan operation for sure as my 2015 is somewhat slow to cool down after start.

Anyone have PN's on these relays? And are they universal to 2011-2017 MY's or do we have PN changes over the years?

Thanks
Eric

Re: Time delay on AC cut-in after start

Posted: Mon Aug 16, 2021 3:38 pm
by BluesBro
aclynn wrote: Fri Aug 13, 2021 1:41 pm
grummin wrote: Mon Jul 15, 2019 12:11 pm That is about the same as my car is doing. I am also not in a huge hurry but it is annoying now that its reaching 100 here in central Texas already. The more I think about it I am thinking it is a compressor issue or the controller that controls the variable displacement. I will post in here if i figure it out.
Its probably too late to let you know what the fix is but hopefully anyone else having the same issue will be able to find this. The issue is upon start up, ac compressor does not engage, takes several minutes before cold air is present. The problem is not the compressor or the controller. The problem is, Excessive heat under the hood causes fan relay damage and failure. There are 3 fan relays. Fan relay 2 if OEM is black, this is usually the failing relay. Checking the other two relays, if OEM they are gray, look for discoloration, if so replace them. Fan 1 is the relay that closest to the engine and gets the most heat. There are two service bulletins that address this problem, the first one from GM is Pl1069. This bulletin refers to No fan or fan continues after key is off but will show you examples of deflective relays. The second GM bulletin is 09-06-03-007A. This bulletin refers to Temperature gage reading HOT and intermittent Fan or inoperative fan. This bulletin is step by step to relocate the 3 relays from the fuse box to the radiator support (passenger side). It includes the part numbers for the additional wiring harness. It says 1.5 hours labor to splice those wires and move the relays.
That second service bulletin is for 2006-2011 impala 9c1's the first I cannot find information on. Not saying it doesn't apply, but the pin outs and harnesses described in the bulletin may not work.

The 2014+ Caprice has PWM fans with the controller mounted directly in front of the AC fan, so I'm not too convinced this would apply there.

Look in the VCM editor the fans at least have a startup delay built in, seems to be set to 1s from the factory but maybe some other parameter offsets that. There is also a parameter to ignition off run time.

The A/C compressor has no such parameters to modify, at least in the VCM editor.

Re: Time delay on AC cut-in after start

Posted: Tue Aug 17, 2021 12:10 am
by elc32955
Well, totally aside from the control methodology the proper functioning of the electric fans is one important element to check out for sure. I've seen a number of different carlines experience electric fan failure which does glop up a number of things. For the folks that work on VW's does "Mark 4" conjure up any bad fan memories? :) Had to help pull the entire nose assembly off a 2000 TDI Beetle that had bad cooling fans once to replace 'em.... not a fun job for sure :)

But yeah, if the cooling fans quit, don't run the prescribed speed, or are slow on run-up this could also dink with the initial AC cooling.... Food for thought! Aside from that, the Frankenstein AC line/return/heat exchanger assembly in my car (MY 12-17) gives me the creeps just looking at it.

Eric