Hello everyone, first time poster, been lurking for a few years whenever my Mom had a question about her HHR.

So I recently inherited her 2009 model year (10/08 mfg) HHR SS model, and it has overheating issues due to the fan not kicking on. This specific model year (correct me if I'm wrong) deleted the cooling fan relay and switched to a "control module" mounted directly on the shroud. From some lurking it seems that the ECM gives the module two different speed outputs to the fan based on engine parameters (coolant temp, IAT, and A/C demand). Without a schematic this is all speculation.

I havent troubleshot it yet because I dont know how it works and was looking for a good source for a schematic. I'm pretty sure the problem is in between the ECM and the fan's ground because I have climbing temperature indications on the dash as well as with the AC on full blast it still dosent kick on.

If anyone has a source for a schematic it would really help me out, I can't afford the shop manual due to living situations.

There seems to be much cheaper options for the factory service manual on sketchy looking websites. If anyone has had experience using these please let me know!

 

The module does go bad. Somebody not too long ago found that they could get just the module. SEARCH phrase "fan module" will probably help, I don't have enough time in my life to go through all of the posts that resulted.

You can test the fan by jumping around the module. The ECU is rarely at fault.

Unless you know how to deal with CAN BUS systems the schema are useless.

There is a site that used to have online GM manuals. It is devoted to "great prize of north america", figure that out for yourself (it's a Pontiac). Don't ask anymore, that's the only hint.

 

Thankyou for the quick response donbrew! I will try hotwiring the fan to see if the module is bad.

I will investigate that lead on the info, I opened either a Chilton's or Haynes' in Autozone and the electrical info was pretty underwhelming. There are a few sites like repairsurge.com, but it looks like a scam.

Anyways thanks again, i'll get back with results tomorrow after I probe that mother trucker!

 

Welcome to the site! Any codes ? Could it be the other cooling system problems, stuck thermostat? Old Dexcool? The car is seven years old .

 

CAN BUS is a different animal from direct wiring, don"t be surprised if you see odd results with a VOM.

 

Hey so I finally got some time to look at it, and the fan motor is definitely bad, totally open circuit. Feel like an idiot for not just checking it first
(she had that module replaced by a mechanic last summer, guess I thought it would be some complex electrical issue.)

Donbrew you were right about CAN bus being complicated, there's some youtube videos that explain it, all of the control modules speak to each other in binary pain in the dick for the home mechanic without an expensive scan tool or an o-scope. I'm wondering if buying a tech 2 clone may be a good investment for the future.

Oldblue, it's definately the fan that's making it overheat, but I intend do a flush sometime this summer. I'm digging those wheels you have in your picture! Gives me an old school vibe.

Thanks for the help guys

 

At the age of your ride , I'd change the thermostat and Dexcool, both are known to start headed south after 5 years!
Thanks for the nod to my ride!!