Cooling fan wires were cut, after splicing them together the fans still do not work

MVANN74

MEMBER
2008 PONTIAC GRAND PRIX
5.3L
V8
2WD
AUTOMATIC
143,895 MILES

I have the car listed above GXP model. Recently I had an engine installed. Car was running hot and discovered the cooling fans were not working. Upon further investigation I found that the wires from fan to fuse box were cut. Please see attached photos. The wires are same colors 8n both ends but when I spliced them together the fan did not work. I direct wired fan to battery and fan works fine. Used test light power is good 8n relay spots. What am I missing here?

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Thursday, June 23rd, 2022 AT 9:56 PM

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

I just want to make sure I understand what I am seeing.

You have both sides of the wiring; it was just cut? Most likely when someone was removing the radiator, they just cut the wiring to remove it.

If that is the case, then we need to connect the wiring back together, color to color and then we need to start doing some testing.

I can only suspect we have a relay issue so let's start with using the wiring diagram and check power on each of the wires when the engine is on.

https://www.2carpros.com/articles/how-to-check-wiring

Then we can remove the fan relays and jump the terminals to see when the fans come on.

Basically, if the relays are ok and can be jumped to power the fans then we know the issue is not from the relay to the fan.

We can assume the ECM is not grounding the relays but let's get to this point and go from there.

Thanks

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