Hi all,

This is my first post, so please go easy on me...... I have searched the forum, but cannot find an answer to my questions.

I have 2009 H3 Alpha, with 152k km's on the clock. It is a GCC (Gulf Cooperation Council) spec vehicle and I am based in the United Arab Emirates.

I took the H3 for a desert drive a few days ago and it severely overheated, the HPRV on the AC lines blew off and the power was reduced. To be on the safe side, I had the truck recovered and taken to a garage.

I have since replaced the radiator (due to leaks), the water pump, thermostat, oil / oil filter and coolant change, and had the AC system vacuumed and re-charged.

Now my questions are;

1. Do all H3 Alpha's have twin electric AC condenser fans installed from the factory? Or is it just region specific, i.e. GCC spec cars? The fans sit between the grill and the AC condenser.
2. Should these fans run all of the time? Do they only engage when the AC is on, or should they kick in a certain temp? I checked the fuse for the fans, and it is fine.

Appreciate any help an guidance on this. I have attached a photo of one of the two fans, between the grill to help explain.

Thanks


One of two fans

 

Now my questions are;
Do all H3 Alpha's have twin electric AC condenser fans installed from the factory?
NO.

Or is it just region specific, i.e. GCC spec cars? The fans sit between the grill and the AC condenser.
EU and Mid-East Imports.

Should these fans run all of the time?
NO

Do they only engage when the AC is on, or should they kick in a certain temp? I checked the fuse for the fans, and it is fine.
YES to both

 

Hi Doc Olds,

Thanks for your reply…. Much appreciated.

Just to clarify on point 2:

Should the condenser fans kick in immediately when the AC is turned on?

Or

Should they kick in once the car temp reaches a certain level?


The air temp over here is already 110 degrees plus, so the AC is on all of the time when driving, but I am yet to see the fans ever kick in and I am keen to ensure I don’t put undue stress on the condenser.

thanks again

 

As I understand it, the factory fans on/off is controlled by the PCM. On when AC compressor clutch is activated, or ON at a certain coolant temp like anything over 200F. Outside air temp is irrelevant.

Try jumping the fan circuit with 12V+ to the positive wire and see if they turn on to rule out the fan motors. We do not have those here in the US, I do not know if they use a separate relay or breaker, but look for those and a fuse.

Good luck.

 

hopefully they have not replaced the ECU with a US spec one as those would not have been programmed with fan support.

 

Thank you again - will give your suggestion a go.

 

This would actually make sense…. I believe previous owner may have replaced the ECU to fix some other issues…..!

Can you advise how I can check this? Is the ECU module accessible?

 

ECU is the PCM here is a link that explains the location on the removal instructions https://www.pcmofnc.com/install/Humm...02006-2009.pdf

 

Thanks Bronxteck.

I will check with the place that replaced the PCM / ECU unit.

I have not noticed anything else on the car not operating correctly, but that’s not to say some other things aren’t working.

Do you think it would make more sense to leave the PCM unit alone (and not risk disrupting anything else) just re-wire the fans using a fuse tap, directly into a spare slot in the fuse box, that is powered on once the car turns on?


[img]blob:https://www.hummerforums.com/40869d9f-7096-4d31-b608-f55743f7e62f[/img]

 

If ecu was replaced, and not flashed with the right program (the US) it wont run the fan. The SA model program has the fan tables edited.
basically, fan 1 runs at 102, fan 2 at 107 celcius and fan 1 runs at ac pressure above 170 psi, fan 2 above 270 psi. Fans turn off at any speed above 60-70 kph.
If you have access to hptuners (a tuner), tuning the fan is very easy .
It would be normal for the fan not to run immediately with ac. It takes a few ac compressor cycles to build pressure in the system to 170 psi. As for without ac, the alpha wont go to 102 just idling.