Cooling fan issues

[antman450]

I have an 11 GT that I stripped out completely and is effectively not for road use (however still drivable on the road). Nonethelss, I was drving it on the street in traffic and it overheated. I tested by letting it idle for a long time sitting still and the car started to overheat and the fan never came on. I am thinking it may be a bad fan motor, so I will need to test this. I have already tested all relays and fuses. I did not however check the fan relay. I don'yt know where it is. If someone could tell me, that would be great. But I was thinking if the fan motor is good I would put in a manual fan switch.

Any ideas on this? Should I just run some 10 guage wire straight to the fan and then a two pole switch on my center panel? Or is there a better way?

 

[ArizonaBOSS]

http://iihs.net/fsm/?d=711&f=033 - Cooling Fan.pdf

The relays are in the engine bay fuse box according to that diagram. Not sure which ones they are but the Owner's Manual should say.
I have never had a problem with the fan activating (typically comes on at 183*F), check those relays and the wiring coming out of the fuse box that runs to the fan itself.

Also if there is no problem with the wiring, I strongly suggest going to the SVT fan assembly.

 

[BigTaco]

http://iihs.net/fsm/?d=711&f=033 - Cooling Fan.pdf

The relays are in the engine bay fuse box according to that diagram. Not sure which ones they are but the Owner's Manual should say.
I have never had a problem with the fan activating (typically comes on at 183*F), check those relays and the wiring coming out of the fuse box that runs to the fan itself.

Also if there is no problem with the wiring, I strongly suggest going to the SVT fan assembly.

Hella this^

 

[antman450]

http://iihs.net/fsm/?d=711&f=033 - Cooling Fan.pdf

The relays are in the engine bay fuse box according to that diagram. Not sure which ones they are but the Owner's Manual should say.
I have never had a problem with the fan activating (typically comes on at 183*F), check those relays and the wiring coming out of the fuse box that runs to the fan itself.

Also if there is no problem with the wiring, I strongly suggest going to the SVT fan assembly.

I switched the relays around and everything else worked fine, so those should be good. All the relays are the same. I swapped them with the other relays that work. I forget exactly what those were for but I tested the component they control and they worked fine. The wires all look good too. I will test the fan motor but ultimately I would like to put it on a manual switch. Anyone know of a good way to add a relay in (basically which one to use) that I can connect to a toggle switch on my center panel?

 

[BigTaco]

I would just replace the fan assemble since the toggle doesn’t really fix the problem. That assembly may stop working even with a toggle at some point in the not so distant future....

 

[antman450]

Fan is bad. Got the SVT fan. What do any of you guys think is the easiest way to add a manual switch. Should I just add a wire to the relay in the fuse box? I want to be able to turn it on when I feel like it as well.

 

[ArizonaBOSS]

My GUESS is that the best way to do this would be to tap a line into the wire that turns on the OEM relay for the fan, that way you are not overloading the fan when/if the ECU commands the fan to activate even if you already have the fan switched on manually (as opposed to two separate power lines to fan).

12V from battery --> 5A fuse --> Switch --> Splice/tap OEM fan relay signal line.

Attempt at your own risk--haven't thought this out too much and suggest you do your own research before attempting.

 

[TMSBOSS]

Diode up stream to protect processor?

 

[antman450]

So, bought a new fan (GT500) and it still does not turn on. I am over troubleshooting this and going to just add a manual switch. Any ideas on a relay part number?

 

[racer47]

Any ideas on a relay part number?

You need something like this. I got this to do the same thing, add a manual fan switch. I just have not got around to it yet.

 

[antman450]

I got this and I am going to run 10 ga wire from battery through switch and 40 amp fuse. Then I will run a ground through a switch in my center panel.

https://www.summitracing.com/parts/aww-500532

@ArizonaBOSS I thought about your idea but I don't want to try to find the darn wire. I am sure I cut something somewhere I should not have. The only other thing would be a bad thermostat or sensor. I really think the former is far more likely as I got somewhat overzealous with the cutting. LOL

 

[DocB]

You may want to consider checking your plastic fuse box and make sure it is not "tweeked", or one corner sittting on the inner fender housing.
This will cause a relay to work loose (if ever so slightly) and the fan will not come on.
Next time the fan does not come on, try pressing down hard on the high speed fan relay in the box and see if the fan turns on.

 

[Grant 302]

Test continuity between the relays and the fan pigtail. Then between the relays and the PCM.

http://iihs.net/fsm/?d=711&f=011 - Fuse and Relay Information.pdf

 

[Grant 302]

12V from battery --> 5A fuse --> Switch --> Splice/tap OEM fan relay signal line.

Attempt at your own risk--haven't thought this out too much and suggest you do your own research before attempting.

Yeah...the pcm signal line closes the negative side of the relay solenoid. Don't hook it up to the battery. Might damage the PCM even with a 5A fuse.

Adding a switch to the signal line needs to connect to ground. Doesn't need to be fused IMO as it's all fused on the hot side. Grn/blu #34 on the PCM for the low speed fan.