Radiator fans problem
Thread Starter
Drifting
Joined: Jun 2004
Posts: 1,627
Likes: 143
From: Goodyear Az
Radiator fans problem
The problem: when the low temperature turn-on setting is reached (219F) only the passenger side fan turns on. (Left side?)
What I've checked so far:
Also, I thought that they are supposed to start at ~185F when the AC is on? They don't... the passenger side fan starts when 219F is reached, whether the AC is on or off, and I *think* it's running in high speed mode, but I'm not sure.
Any thoughts on why they will both run with the jumper, but only the passenger side starts at 219F? My guess is that COOLFAN3 relay isn't working correctly.
What I've checked so far:
- fuses 14, 46, and 49 are good per multi-meter check
- both fans turn easily by hand, no plastic bags, etc.
- I removed relay 45 and jumpered from pin G2 (hot) to pin E3 (load) and both fans turned on, so I know they both work
Also, I thought that they are supposed to start at ~185F when the AC is on? They don't... the passenger side fan starts when 219F is reached, whether the AC is on or off, and I *think* it's running in high speed mode, but I'm not sure.
Any thoughts on why they will both run with the jumper, but only the passenger side starts at 219F? My guess is that COOLFAN3 relay isn't working correctly.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
Both fans run together whenever needed. They either run in series which is low-speed or in parallel which is high-speed. Both fan grounds are located at the top right forward frame rail directly adjacent to the hood riser.
Thread Starter
Drifting
Joined: Jun 2004
Posts: 1,627
Likes: 143
From: Goodyear Az
I understand how it's supposed to work, what I don't understand is why they would both run when the low speed relay is jumpered but only the passenger side fan runs when commanded by the PCM. I have a blown 402 so next up I'm going to take a look at the PCM temperature settings today, but I'm still confused how to figure out if any of the relays are bad.
Last edited by nuke61; Jul 2, 2011 at 09:48 AM.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
The relays change the ground paths to run both in either low or high speed modes. The driver's side fan is the hard one to know if its running but in low speed, the power to the passenger fan, is passing through the driver's side fan. Bill's schematic will show you all of this if you know how to read it. Yes, you could have a relay bad but the to find out is y removing the cover of the relay and manually close it. Do the low speed one first.
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
It sounds like relay 45 is either bad or the PCM output for relay 45 isn't working (wiring or the PCM itself). I suspect your PCM has been programmed with new fan turn-on temps and the high speed turn-on is now 219 degrees. So, the car has no fans until the high speed fan temp is reached and then it turns-on the RHS fan.
Relay 44 & 45 are used to run both fans in low speed.
Relay 44 & 45 are used to run the LHS fan in high speed.
Relay 43 is used to run the RHS fan in high speed.
Looking at the above and your post that the drivers side or LHS fan isn't working means it must be relay 44 or 45. But, you already jumpered relay 45 and proved 44 would work for the low speed. So, the problem is likely relay 45.
Swap relay 43 & 45. I bet you will have low speed and the LHS fan only in high speed.
FYI, the fans run in LOW speed when the AC is turned on, not high speed.
Peter
Relay 44 & 45 are used to run both fans in low speed.
Relay 44 & 45 are used to run the LHS fan in high speed.
Relay 43 is used to run the RHS fan in high speed.
Looking at the above and your post that the drivers side or LHS fan isn't working means it must be relay 44 or 45. But, you already jumpered relay 45 and proved 44 would work for the low speed. So, the problem is likely relay 45.
Swap relay 43 & 45. I bet you will have low speed and the LHS fan only in high speed.
FYI, the fans run in LOW speed when the AC is turned on, not high speed.
Peter
Thread Starter
Drifting
Joined: Jun 2004
Posts: 1,627
Likes: 143
From: Goodyear Az
You say the passenger side fan turns on and then ask if that's "Left side?".
You mention that both fans turn on when you jumper relay 45. Is that with engine hot or cold?
You are correct in that BOTH the fans should come on at high speed with AC on at 185. But you are saying neither fan comes on with that condition?? or is it just the RH fan that comes on??
You've both narrowed it down to relay 45, so I'll take a look at that. Thanks, I'll update if I get any more information.
Thread Starter
Drifting
Joined: Jun 2004
Posts: 1,627
Likes: 143
From: Goodyear Az
O.K., now it gets even more odd. I downloaded the tune from my car using HP Tuners and the fan settings are:
What's bizarre is that the passenger fan clearly turns on right at 219F, and that temperature is nowhere to be seen in the Fans section in HP Tuners.
- Fan 1 On Temp = 185
- Fan 1 Off Temp = 170
- Fan 1 Enable Speed = 35 mph
- Fan 1 Disable Speed = 25 mph
- Fan 2 On Temp = 200
- Fan 2 Off Temp = 185
- Ignition Off Disable Temp = 284
- Ignition Off Run Time = 1 second
What's bizarre is that the passenger fan clearly turns on right at 219F, and that temperature is nowhere to be seen in the Fans section in HP Tuners.
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Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
Yes, that is odd. I'm not sure how to explain it. My fans operate right at the temps set in the PCM when I watch the coolant temp on the cluster.
You don't happen to have some kind of extra wiring and sensor added to the car??
Peter
You don't happen to have some kind of extra wiring and sensor added to the car??
Peter
Thread Starter
Drifting
Joined: Jun 2004
Posts: 1,627
Likes: 143
From: Goodyear Az
No extras, just PCM tuning. I'm going to change the programming a bit and see how it responds. The car hasn't overheated, but it did get up to 250F and that was too close to overheat for me. It has a new DeWitts radiator in it too, so it surprised me that it got that hot.
