Natomic

Does anyone have an electrical wiring diagram for the cooling fans for the LNF engine? It would really help me solve my problem. My fans sometimes run constantly after the car is off (longer than the 7 mins commanded by the ecm in certain conditions). This drains my battery and makes me have to push start my car in an empty parking lot at midnight in 5*F weather.

Natomic

Help! Seriously if some one has access to AllData or ShopKey i'd give them a few bucks to send me wiring or diagnostic info for this. I thought my problem went away last winter but it has come back again! After I shut off the engine sometimes both cooling fans run continually until the battery dies. I can pull a cooling fan relay to make them stop. Otherwise the cooling system functions normally. This is an intermittent problem that only seems to happen in cold outdoor temps. All the relays and fuses are good. Based on the voltage going to relays, the fans are powered unless switched off by the relays. This is why I need the wiring diagrams to find out how the ECM controls the fans.

Coballin13

Bump for this guy

09CobaltSS1

Does this help?

Natomic

Yes it does! But are you sure this is for LNF? Diagram looks like a more simple Hi/Low operation. I thought LNF fans were pulse width modulated to control fan speeds at different percentages.

09CobaltSS1

That's what comes up in alldata for a 09 Cobalt SS with an LNF engine my friend. As far as I'm aware, all cobalt fan controls are pretty similar across the board with slight variances. All voltages to the fans themselves are controlled via the ecm, which is what controls fan speed percentages. The relays and switches are just what control which vans are turned on/off, which is also ultimately controlled by the ecm as well.

Grave

iTrader: (7)

I know fan speed is percentage based in HPT, but the fans are either on or off (one side only or both).

JapEatr

iTrader: (9)

Correct

TStone

iTrader: (2)

That diagram should be right. I can check GM SI but i'd bet it's the same. They're not PWM

Natomic

Ok thanks everyone! Soon as it gets above 20*F outside today I'll test some wiring haha
09CobaltSS1, thanks and i'll see you soon for my tune

Natomic

In case anyone has the same problem, my fix was to replace both 4-pin fan relays. I believe one of them was sticking occasionally and keeping the fans on.

RyBread761

iTrader: (2)

^ this. Sounds like you have a sticky relay. Replace them first before you really get into the wiring.