Contour Enthusiasts Group Archives Forums General Troubleshooting V6's have two fans, question on overheating.

RogerC:

The A/C is turned on in the following four HVAC modes: Max A/C, Norm A/C, Mix and Defrost.

There are 2 circuits that control the fans:

1 - The PCM controls them when the A/C is either off or on and turns them on at either low or high speed, when needed, depending on engine temp.

2 - With the A/C on, there is a multistage pressure switch in the A/C system that turns the fans on at high speed, independently of the PCM, when the high pressure side of the A/C reaches 285-315 psi and then turns them off when it drops to 220-280 psi. Additionally, that same switch will disable the compressor clutch if the A/C high side pressure reaches 415-445 psi and re-enable it when the pressure drops to 220-280 psi <-- high-limit safety switch.

If you lose your fans, initially the A/C clutch will engage and run until the high limit switch senses an over-pressure condition, when it will turn the A/C clutch off. The A/C will cycle a few times like this until the system gets really hot and then it will stay off for quite a while, hence, no A/C. If you're driving at hwy speeds, there may be enough air flowing through the condenser to keep the pressure low enough to allow the A/C to run, but not usually on very hot days. You may also have engine overheating problems at standing idle or in stop & go traffic. (these were the symptoms on my car)

The problem with the fans is, that over time the bearings tend to sieze, the fans bog down or stall and draw a huge amount of current. If the electronic circuit protector recall (program 00M13, 8 yrs / 100K miles) hasn't been done, you can fry the fan/main wiring harness(es) OR hopefully, blow the 60 amp cooling fan fuse before the harness gets burnt up. Mine blew the 60 amp fuse even though the recall had been done.

So,
1) Check to see if the A/C works for a while before the car warms up. The fans should come on shortly after the A/C is turned on and maybe cycle every 1/2 to 1 minute.
2) If they don't run, check the 60 amp fan fuse in the fuse box (the middle one of the three biggies in there and it is a PITA to replace).
3) With the battery DISCONNECTED for safety, turn the fan blades by hand to see if they turn fairly easily. If one or both seem very stiff or are siezed, you need to replace the fan assy (~$235 from fordpartsonline.com and not a fun job).

See: Cooling fan replacement procedure for the agony (thanks to projectSHO89).

If one of the fans still seems to have good bearings, you can disconnect the bad one (disconnect and save the electronic protection module, if the recall was done) and try to temporarily run on only one fan until you can replace the whole assy (may not work). The electronic protection modules from the recall are located in-line, at the connectors of the fan motors and are weird looking things about 4" long. If the 60 amp fan fuse is blown, you'll oviously need to replace it.

If the above suggestions don't pan out, I don't know what else to say except you've got other problems and prolly need the services of a dealer or knowledgable mechanic.

Kurt

Wasn't there a recall for the fans not operating???

Well, mine must have been under the recall as well. The inline replacements that plug into the fan, then the wiring plugs into that were there.
I didn't do nearly as much to get my fan motor out. I undid the lower plastic skid plate,unhooked & removed the battery, the lower retaining bolts that hold the radiator to the front sub-frame, two bolts that hold the top portion of the fan assembly to the radiator and the wiring for all the switches (altenator, ground, motor switches & some sort or resistor thingy). Then I was able to move the bottom of the radiator enough to pull the unhooked fan assembly out from the bottom (both front wheels up off the ground at least 3 inches). It came out at an angle and went back in the reverse way. If I had to do it now it would take me 1 hour. But it was a learning experience I'll tell you that! For awhile I wasn't sure if I had gotten in over my head..

Y'know Nate, it looked to me like it could've been done the way you described but I did it the hard way. Besides, my cooling system needed flushing and freshening up anyway. It was a PITA and refilling the cooling system is really fun (all that air "burping" and the possible attendant overheating if you're not careful). Some guy named Walter C. Avrea designed it, and he should be:

Kurt

KurtD

My fan unit (shroud and fans) were replaced before the recall . I was reimbursed by Ford as per the recall notice.New fans were of the correct type and did not need the circuit protection, or so they said. Fans turn easily enough by hand and they were running previously in the Mix and Defrost modes, until last Friday.Relay in the fuse panel is OK as I swapped it with the starter relay and the starter engaged. Previuously at startup the fans had run when the selector was in the two modes also, but, not now.
The 60 amp fuse appears to be intact ..the wire viewed through the plastic looks OK.
The engine has run cool since I changed the Thermostat and water pump last fall. Temp gauge stays below the 'N'.
I'll have a go at seeing if the AC will come on at highway speed on the way home tonight.

thanks

Roger:

IIRC, according to the recall, even if the fans were replaced under the recall, the protectors were still supposed to be installed to protect the wiring harnesses.

Does the compressor engage and run? If the comp doesn't run, you won't build up enough pressure on the high side of the A/C system and the fans won't turn on.

There are 2 pressure switches that control the A/C clutch. The high side safety cutout switch and the one in the low side that actually does the cycling of the clutch under normal operating condix.

The A/C comp clutch gets power (confusingly) through the heater blower motor relay, the A/C clutch high pressure cutout switch, the clutch cycling pressure switch and the A/C clutch relay when the HVAC selector is in one of the four A/C enabling positions. There is also a relay that is controlled by the PCM that disengages the A/C at WOT. Any one of which could mess up the A/C system. If the heater blower runs, the blower motor relay is OK.

All the relays, except the blower motor relay (located under the dash somewhere), are in the engine compartment electrical box. The high limit cutout pressure switch is located right in front of the radiator coolant reservoir (switch terminals connected to the pink and pink/blue wires should be normally closed, the other two are open until 285 psi and control the cooling fans). The clutch cycling pressure switch is located on the driver's side of the radiator, below the battery, on the accumulator (closes at 45 psi, opens at 23.5 psi, wire colors: pink and pink/orange, should be normally closed at system off). A low charge (<23.5 or possibly 45 psi) would keep the cycling switch from closing preventing the A/C clutch from engaging.

The schematic for the A/C system is spread out across three pages in the electrical manual, with connections jumping from one page to another, several times. My head is spinning now but I hope this helps you a little with your diagnosis.

Also, check this post: A/C Diagnostic Tests (Thanx projectSHO89)

Kurt

Kurt,
thanks for your energy and advise.

The cooling fans are OK (I think anyway) because they came on when I had been idling for a while after having come off the expressway after about 20 minutes of over 65 mph.
The heater blower runs at all speeds , but the cooling fans will not come on when the 4 HVAC settings are chosen.
I don't think the compressor is coming on.
I performed projectSHO89's diagnostic with the ohm reading between 3 and 4 (he said 5 was good) and the DC voltage came out at around 13.
I will do some more poking around tomorrow and look for what you have suggested. I know relay R4 (A/C clutch relay) is OK since I swapped it with R6 (starter relay) and the starter activated.

thanks again

Roger

Roger:

I made an error in reporting the colors of the wires at the pressure switches. What I called pink should be purple. I'm used to calling it violet, in the electronics racket. It was labled "P" in the schematic, I just didn't read the legend.

Have someone turn the A/C on while you listen at the front of the vehicle, you should hear the comp clutch snap if it's pulling in.

So, pink/blue should be purple/blue and pink/orange should be purple/orange.

Kurt