help troubleshooting rad fan please

[yamamarc]

Hi I figured why my viper is seeing high temps when running roads my fan isn't kicking on!!
on the trails was sticking around 72 to 74*c all day on our way home I have to run some pavement/ice for about 2km! Twice now when coming home my temps would reach 100 to106*c
Once home I checked and fan wasn't running and wife's fan was running and she was in the 90s
I shut them both off then turned the key to the on position and wife's fan started up and mine didn't!!
I'm going to troubleshoot tomorrow and was hoping for some tips to make this fast and easy
First I plan on running wires directly from battery to the fan to make sure it runs.
second will check test relay
third I have a extension cable from the mpi turbo kit for the thermostat connector (part of the kit)
will check this as well. I'm guessing if that cable is bad I wouldn't get any temp readings on my gauge is this correct?
any tips would be greatly appreciated

 

[grizztracks]

All five of the smaller relays are interchangeable. The easiest way to check a relay is to swap it with the tail light relay then turn the key on to see if the display and tail light turn on. There have been some reports of bad fan motors.

 

[yamamarc]

All five of the smaller relays are interchangeable. The easiest way to check a relay is to swap it with the tail light relay then turn the key on to see if the display and tail light turn on. There have been some reports of bad fan motors.

Thank you so much for your reply Grizz
That will save me time with the relays...
I will swap like you suggest

Thanks again

 

[yamamarc]

okay I check the fuse and relay and they are both good!! I ran a wire from battery and fan runs fine!!!
Next I will check the cable extention supplied with mpi kit (plugs into thermostat housing to original cable!!)
just a question does the cable from the thermostat housing relay the temp to ecu and send signal to start fan??
If the cable was shorted would I still get a temp reading on gauges?
if this cable wasn't seated right would it throw a code and not start?
thanks
marc

 

[TD Max]

Someone with more knowledge can answer, but my first question is does the ECM signal the fan or does the fan have a simple thermal switch? Most modern engines now signal from the ECM.

I'll add that since this seems to be an uncommon issue, the fan itself has been verified to work, and coincides with your turbo install I would go back in and check your work closely.

In other words the first place to look is the last place you were messin'...

 

[grizztracks]

Someone with more knowledge can answer, but my first question is does the ECM signal the fan or does the fan have a simple thermal switch? Most modern engines now signal from the ECM.

The fan relay is controlled by the ECU

 

[yamamarc]

Someone with more knowledge can answer, but my first question is does the ECM signal the fan or does the fan have a simple thermal switch? Most modern engines now signal from the ECM.

I checked the extension cable from thermostat with voltmeter and it's OK too
But I think this cable is only for the temp light when warming up when starting..
Not sure if there is another relay or fuse somewhere else?

 

[yamamarc]

The fan relay is controlled by the ECU

then for some reason it's not signalling

 

[grizztracks]

I checked the extension cable from thermostat with voltmeter and it's OK too
But I think this cable is only for the temp light when warming up when starting..
Not sure if there is another relay or fuse somewhere else?

 

[grizztracks]

The ECU signal is a grounding control signal to the the relay.

 

[yamamarc]

The ECU signal is a grounding control signal to the the relay.

possible loose wire in the circuit?

 

[yamamarc]

ok I checked all wires everything looks ok!!!
I ran out of time today (have to go to work soon)
So tomorrow I'll check that I have power at the relay (lower left pin in of relay seat in fuse box) can this be done with key on or does sled have to be running?
if I have power at relay I will start machine and idle it to temp where the fan is suppose to kick on and check the fan connector to make sure there is power there also!
What temp should fan kick on?
If there is power at the connector then Ill know it's something with fan itself!! Even though I ran a wire directly from battery and proved fan was working I am still going to check!
If all fails I'm going to run a temporary wire with fuse and switch to fan and switch it on when needed!
Once the seasons over I rip sled apart and troubleshoot further!!!
any other suggestions would by greatly appreciated!!!!!
and Grizz thank you for taking this time to respond
I owe you buddy!!

Marc

 

[yamamarc]

one other thing I will need to check that could have interrupted the circuit! I was looking at the wiring diagram and
pin 10 on the 16 pin main harness connector!
the gem controller harness get connected between the 16 pin connector (maybe corrosion on pin 10 or broken wire from male t female side of gem controller harness!!

 

[Goober01]

one other thing I will need to check that could have interrupted the circuit! I was looking at the wiring diagram and
pin 10 on the 16 pin main harness connector!
the gem controller harness get connected between the 16 pin connector (maybe corrosion on pin 10 or broken wire from male t female side of gem controller harness!!

I had a problem when I removed my muffler,and reinstalled I knocked the plug off the temp sensor very hard to see it but that did set a code 118 just a idea

 

[yamamarc]

I had a problem when I removed my muffler,and reinstalled I knocked the plug off the temp sensor very hard to see it but that did set a code 118 just a idea

did this affect you fan operation?
I have no codes and my engine temps are showing up on gauge display