Radiator Fan problems

[smcbride11]

I had an issue the other day when my engine ('04 Renny) wouldn't shut off even with the key out... I ended up putting it in gear and letting the clutch out until she stalled.

Since then, I've had a check engine light and when I got the codes pulled this morning I ended up with:

462 (Fuel Level Sensor Low Voltage)
480 (Cooling Fan 1 Malfunction)
481 (Cooling Fan 2 Malfunction)

I'm tackling the radiator fan first, but I'm looking for a good way to test the fan to see if the problem is the fan itself, an electrical ground problem, or a problem with the relay. The codes cleared up on my way home from lunch today, so the intermittent nature is making me think relay first (since I've already had to replace my horn relay and all the wiring looks good).

What's the best way to test a radiator fan for proper function?

 

[Powerslave]

Manually apply voltages to the wires with it unplugged from the harnesses. The failure would mean the ECM is not detecting they are turning on, IF they are turning on. There are relays for each fan too. Easy part is relays first, but you got to buy or temp swap from another location. Then test the fans of they actually are working by applying 12V to them. It's all how much you know about electricity and wiring.

 

[tjkj2002]

I had an issue the other day when my engine ('04 Renny) wouldn't shut off even with the key out... I ended up putting it in gear and letting the clutch out until she stalled.

Since then, I've had a check engine light and when I got the codes pulled this morning I ended up with:

462 (Fuel Level Sensor Low Voltage)
480 (Cooling Fan 1 Malfunction)
481 (Cooling Fan 2 Malfunction)

I'm tackling the radiator fan first, but I'm looking for a good way to test the fan to see if the problem is the fan itself, an electrical ground problem, or a problem with the relay. The codes cleared up on my way home from lunch today, so the intermittent nature is making me think relay first (since I've already had to replace my horn relay and all the wiring looks good).

What's the best way to test a radiator fan for proper function?

The fan relay is located about 10" below the battery on the inner fender.The new replacement will not look like the old one,they updated the relay with a larger heatsink.

Sounds like you overheated the engine,the reason for the inability to shut of normally.Might want to check out the entire cooling system also.

 

[kb0nly]

Wait a sec... tjkj... Can you elaborate on that? If it gets overheated you can't shut the engine off? Seems odd to me, if its overheating you would want the damn thing to shut off now!

 

[tjkj2002]

Wait a sec... tjkj... Can you elaborate on that? If it gets overheated you can't shut the engine off? Seems odd to me, if its overheating you would want the damn thing to shut off now!

In some cases your engine can be so hot that it will continue to run after you "shut it off",also known a dieseling.There are other factors also,overheated wiring can also cause the same issue if it overheats the ASD relay.

Oh and in some cases shutting off a engine that is overheating can be worse then leaving it to run at idle till it cools down some.When you shut off your engine the temps will continue to rise for some time before the engine actually starts cooling off,the temps may continue to rise for uo to 30mins or more before it starts decreasing.

 

[smcbride11]

In some cases your engine can be so hot that it will continue to run after you "shut it off",also known a dieseling.There are other factors also,overheated wiring can also cause the same issue if it overheats the ASD relay.

I was wondering about that - I had this happen once before (when my horn relay went), and I was worried that it might be traditional dieseling... I replaced the spark plugs and ran some Techron through to hopefully clean up some deposits, and it's been okay for about six months now.

I don't think the engine itself overheated, since I had started cold and driven three miles in a cold rain when it happened... Overheated wiring makes some sense, though - that I could definitely see being an issue.

 

[kb0nly]

Ok.. Dieseling yes... But the way you said it i thought you meant something in the vehicle, as in the computer or otherwise, was preventing shutdown.

 

[JeepJeepster]

I always figured dieseling happened more on a carbed engine than a EFI engine. When you shut an EFI engine off both the gas and spark is shut off but with a carbed engine the gas is always available and the heat ignites it. I would say there is a small amount of gas left to burn but it should burn off failry quick. Just guessing though..

 

[kb0nly]

I always figured dieseling happened more on a carbed engine than a EFI engine. When you shut an EFI engine off both the gas and spark is shut off but with a carbed engine the gas is always available and the heat ignites it. I would say there is a small amount of gas left to burn but it should burn off failry quick. Just guessing though..

Yeah my thoughts as well.. Unless of course you got a leaking fuel injector.

 

[Powerslave]

I always figured dieseling happened more on a carbed engine than a EFI engine. When you shut an EFI engine off both the gas and spark is shut off but with a carbed engine the gas is always available and the heat ignites it. I would say there is a small amount of gas left to burn but it should burn off failry quick. Just guessing though..

That is correct, these SMPI systems will not run after you shut them down. The old TBI (sputter injection - leaks), and carburetor engines; where gas would continue to get in, will do that. I have never seen a new FI engine diesel, EVER. I had a carb one that did, but every FI engine car I had, NEVER did.

It also has nothing to do with the spark, it is hot spots in the cylinder that causes the gas to continue to fire; but the gas has to be leaking in with FI. With carbs, well, it will continue as long as it takes sometimes, but usually going WOT (press the gas all the way down) will stop it.

 

[tjkj2002]

Powerslave Quote:
Originally Posted by JeepJeepster
I always figured dieseling happened more on a carbed engine than a EFI engine. When you shut an EFI engine off both the gas and spark is shut off but with a carbed engine the gas is always available and the heat ignites it. I would say there is a small amount of gas left to burn but it should burn off failry quick. Just guessing though..

That is correct, these SMPI systems will not run after you shut them down. The old TBI (sputter injection - leaks), and carburetor engines; where gas would continue to get in, will do that. I have never seen a new FI engine diesel, EVER. I had a carb one that did, but every FI engine car I had, NEVER did.

It also has nothing to do with the spark, it is hot spots in the cylinder that causes the gas to continue to fire; but the gas has to be leaking in with FI. With carbs, well, it will continue as long as it takes sometimes, but usually going WOT (press the gas all the way down) will stop it.

Yes dieseling is extremely rare on on FI engines but it can happen but like I stated it is very rare(and may or may not use gas as the fuel),not saying it was the OP problem but just throwing it out there.A electrical problem is most likely his problem.

 

[jnaut]

Oh and in some cases shutting off a engine that is overheating can be worse then leaving it to run at idle till it cools down some.When you shut off your engine the temps will continue to rise for some time before the engine actually starts cooling off,the temps may continue to rise for uo to 30mins or more before it starts decreasing.

X2 on this one. If you have an engine which is functioning relatively normally but has overheated due to specific conditions such a heavy loading in hot weather (or something like that) letting it idle for a while with proper coolant running through it will bring it down to normal operating temperature. A sudden stop of the engine will merely boil the coolant left in the block.

 

[Mangate]

462 (Fuel Level Sensor Low Voltage)
480 (Cooling Fan 1 Malfunction)
481 (Cooling Fan 2 Malfunction)

What does Cooling Fan 1 and 2 mean? I thought there was only one fan.
The only problem I've ever had with my 02 was the cooling fan relay, that one under the battery. Later models (from 05 I think) had it relocated to the power distribution box and changed from an electronic relay to electromechanical.

My problem was that the relay contacts were obviously corroded so the extra resistance generated alot of heat and started to melt the plastic. Cleaning the contacts only lasted a day or to and I got a warning again (I think it was P1491 Cooling Fan Relay Control Circuit).
I cut off the connector, filed the relay contacts down to the copper and soldered the wires straight onto the relay. No problems since, that was 2 years ago.

Anyway, what I'm saying is that just because you bought a new relay and it solved your problem the cause could have been bad contacts so check that they have no corrosion.

Can you hear the fan running when you put the A/C on?

The fan relay connector has 4 wires, Dark Blue/Pink, Yellow, Light Green, Black/Orange.

If you pull the plug from the relay and short the Dark Blue/Pink to Black/Orange with a small jumper wire the fan should operate even with the ignition off. If this works it would indicate a bad relay or problem in the control from the PCM.
If it doesn't work then check for 12 volts on the Dark Blue/Pink wire and a good connection to earth on the Black/Orange wire.

 

[Redbone]

What would one do to kill the engine if this happens in a vehicle with auto ******?

 

[ridenby]

What would one do to kill the engine if this happens in a vehicle with auto ******?

Shoot it with your .45?

 

[tjkj2002]

What would one do to kill the engine if this happens in a vehicle with auto ******?

Put it in gear and power brake it.

What does Cooling Fan 1 and 2 mean? I thought there was only one fan.

1 cooling fan but 2 speeds.

 

[Powerslave]

Your fan will have a wiring harness, with three wires to it, LOW, HIGH, GROUND.

Remove the harness, and ground the ground wire. Then apply 12V to the LOW and 12V to the high sides, and see if the fan turns on with those. If the fan turns on with direct wiring, then you have a relay problem; not so uncommon with electric fan cooled motors.

 

[kb0nly]

Also turn the AC on and the fan should come on right away, if not then test the fan as Powerslave suggested, and if the fan works then yes its probably just the fan controller.

 

[smcbride11]

Also turn the AC on and the fan should come on right away, if not then test the fan as Powerslave suggested, and if the fan works then yes its probably just the fan controller.

The fan doesn't turn on when the AC's on... But my understanding (from the Haynes manual) is that the fan won't turn on until operating temp is 176*F without the A/C on or 202*F with the A/C on. I'm certainly not running at those temps in my driveway. Having said all that, though, the fan's still not coming on.

I did replace both relays (I've got relays in the under-hood power distro center) to no avail. The visible wiring all looks good, so the next step is to check and probably replace the fan itself - which would have been the first step if it wasn't getting dark at 4:00

 

[tjkj2002]

The fan doesn't turn on when the AC's on... But my understanding (from the Haynes manual) is that the fan won't turn on until operating temp is 176*F without the A/C on or 202*F with the A/C on. I'm certainly not running at those temps in my driveway. Having said all that, though, the fan's still not coming on.

I did replace both relays (I've got relays in the under-hood power distro center) to no avail. The visible wiring all looks good, so the next step is to check and probably replace the fan itself - which would have been the first step if it wasn't getting dark at 4:00

You got to check the main fan relay that is not in the fuse box,it's about 10" directly under the battery on the inner fender.