Need help with 07 TBSS clutch fan settings

[Markrose76]

Does anyone have settings for EV clutch fan that would help with keeping AC cool at idle? The AC system in the TBSS leaves something to be desired. I replaced the compressor because the clutch locked up. I also replaced the orifice tube and accumulator. Had it pressure tested and charged, everything is good but at idle the AC gets warmer. Before I convert to efans I figured I'd try to tune the clutch fan first.

[blindsquirrel]

Does the fan work like it's supposed to when you command it in the scanner? It usually doesn't take a huge amount of airflow to manage the A/C heat load. Unless something is wrong there should not be any issues using the stock fan settings. The EV clutches are very failure prone.

The EV clutch is really slow to respond to commands (even when not broken). It makes up for that by having an extremely large fan blade. And as a counter to your 'leaves something to be desired' comment, the A/C in my '06 Envoy will get so cold at idle that it hurts a little bit.

[Markrose76]

Does the fan work like it's supposed to when you command it in the scanner? It usually doesn't take a huge amount of airflow to manage the A/C heat load. Unless something is wrong there should not be any issues using the stock fan settings. The EV clutches are very failure prone.

The EV clutch is really slow to respond to commands (even when not broken). It makes up for that by having an extremely large fan blade. And as a counter to your 'leaves something to be desired' comment, the A/C in my '06 Envoy will get so cold at idle that it hurts a little bit.

Yes, the fan works as it should. No overheating or running hot. I wish I had your "get so cold at idle that it hurts a little bit" issue. I have read a couple posts regarding the EV fan settings being changed to help the issue but the posts are several years old and not entirely descriptive on what exact parameters need adjusted or what they need adjusted to. If someone could point me in the right direction I'd be appreciative.

[edcmat-l1]

Sounds like the system is under charged.

[Markrose76]

Sounds like the system is under charged.

I thought that too but it has the required 1.9lbs of freon. I have a set of gauges coming today to check high and low pressures. Using my fluke with temp probe the output temp at the vent at idle is only 57f. When driving it gets a little cooler but not much.

[Alvin]

you likely have something else going on. Has the condenser been blocked by dirt/sand? common from where I'm from.

[Markrose76]

you likely have something else going on. Has the condenser been blocked by dirt/sand? common from where I'm from.

Not that I am aware of. The only time the system was opened is when I replaced the stock compressor and stuff and it never left my garage. I'll see what the gauges tell me when they arrive.

[Alvin]

The fins will get blocked by debris. Externally.. not internally.

[2xLS1]

Does the TBSS use that same wonky fan the the I5 TB uses? We had a 02 TB I5 that the AC always sucked for blowing cold air when the vehicle was stopped. It was horrible if the vehicle was just started after sitting for a while in hot weather. As soon as the vehicle would start to move it would immediately start blowing colder air out the vents.

[Markrose76]

The fins will get blocked by debris. Externally.. not internally.

I believe its not blocked but I will double check that.

[Alvin]

Does the TBSS use that same wonky fan the the I5 TB uses? We had a 02 TB I5 that the AC always sucked for blowing cold air when the vehicle was stopped. It was horrible if the vehicle was just started after sitting for a while in hot weather. As soon as the vehicle would start to move it would immediately start blowing colder air out the vents.

yes.. computer controlled electroviscus clutch. They have problems.. usually lock up when they go back. But i assume it could go the other way.

I'd do electric fans if it was confirmed bad. No fan is going to be going down the road at 45mph. If the A/C cools at speed that would be a good thing to look at.

[Markrose76]

yes.. computer controlled electroviscus clutch. They have problems.. usually lock up when they go back. But i assume it could go the other way.

I'd do electric fans if it was confirmed bad. No fan is going to be going down the road at 45mph. If the A/C cools at speed that would be a good thing to look at.

Is it ok if I pm you?

[Alvin]

sure but better to ask questions here. might help someone else in the future.

[Markrose76]

sure but better to ask questions here. might help someone else in the future.

Ok. Would you suggest going to efans? Would that help my issue? I just bought the truck 3 months ago and replaced the AC parts a few weeks ago when I discovered the clutch was shot. It just started getting hot here in southern Ohio. Yesterday it was 85 and a little humid. When I got in the truck and fired up the AC it was blowing hot as expected then as I drove it did get colder but not ice cold and it took a long time 15-20 mins to get there. Then at a stop light it would get warmer. I checked the vent output when I got home. At idle my temp probe showed 57F then if I idled it up to 1500 rpm it would start to come down to 50f ish. I checked the freon with a cheap gauge and it showed full.

[Alvin]

Ok. Would you suggest going to efans? Would that help my issue? I just bought the truck 3 months ago and replaced the AC parts a few weeks ago when I discovered the clutch was shot. It just started getting hot here in southern Ohio. Yesterday it was 85 and a little humid. When I got in the truck and fired up the AC it was blowing hot as expected then as I drove it did get colder but not ice cold and it took a long time 15-20 mins to get there. Then at a stop light it would get warmer. I checked the vent output when I got home. At idle my temp probe showed 57F then if I idled it up to 1500 rpm it would start to come down to 50f ish. I checked the freon with a cheap gauge and it showed full.

It sounds like you have another issue to be honest. If you diagnose a bad fan clutch which is computer controlled on these. Than I would do electric fans because of the cost replacing the stock EV setup + I've literally seen 30+ rwhp putting electric fans on trailblazer SS's. I wouldn't guarantee anyone picking up that much.. but a mechanical fan locked up even a little at 6000 RPM is a HUGE amount of power loss...

[Markrose76]

It sounds like you have another issue to be honest. If you diagnose a bad fan clutch which is computer controlled on these. Than I would do electric fans because of the cost replacing the stock EV setup + I've literally seen 30+ rwhp putting electric fans on trailblazer SS's. I wouldn't guarantee anyone picking up that much.. but a mechanical fan locked up even a little at 6000 RPM is a HUGE amount of power loss...

I'll pull the grill off and check the condenser when I get home. Hopefully my gauge set will be there and I'll check pressures too. Based on my symptoms where would you start troubleshooting?

[Alvin]

Does it cool at speed? If so it might be a fan

Have a good A/C tech put the system on a vacuum, check for leaks, refill with proper amount.

[Markrose76]

Does it cool at speed? If so it might be a fan

Have a good A/C tech put the system on a vacuum, check for leaks, refill with proper amount.

It does get cool at speed. When I replaced the compressor I had a shop pull vacuum and they said it held then they filled with 1.9lbs of r134a.

[blindsquirrel]

How many times has the system been opened, if you know? It's real common for guys to follow instructions that tell you to add X amount of oil when replacing components, even if there was no oil left in the old part... do that a few times and the lower 1/3 of the condenser ends up plugged up solid with oil that never goes anywhere. A/C systems that've had many hands on them over the years can be a giant pain in the ass.

[Markrose76]

How many times has the system been opened, if you know? It's real common for guys to follow instructions that tell you to add X amount of oil when replacing components, even if there was no oil left in the old part... do that a few times and the lower 1/3 of the condenser ends up plugged up solid with oil that never goes anywhere. A/C systems that've had many hands on them over the years can be a giant pain in the ass.

Honestly I have no idea how many time its been open. The compressor I replaced was the stock original and it had Freon in it when I replaced it. The orifice tube was clean as well. When I replace the compressor I put 8oz of PAG46 in it.