Auxiliary Fan?

Update:


Installed the new fan motor and now have a working fan. The fan comes on when the A/C is turned on. It would turn off when switched off (less than ~220 or so). If engine temp sender reads higher than ~220 or so the fan will stay on.

Initially when testing to see when the fan would come on without the A/C on I couldn't get the engine temp high enough while idling (Ambient air temp 71F). What I did was run the engine until the engine temp was normal then turned off the engine and let it heat soak for several minutes.

Then I turned the key to the 'On' position (engine off/no A/C) and the fan did kick on. Awesome! I then started the engine and waited & watched the fan. As the dash gauge dropped to 200 or so the fan continued to run (no A/C). I believe the reading between the dash gauge sensor and the RH manifold sensor differ. The fan will stay on until the RH sensor dictates when to turn off fan.

Key off and the fan shuts off.

So yes to confirm this fans purpose is to aid in moving air into the A/C condenser then onto the radiator/clutch fan during idle and/or slow speed situations.

dougrainer wrote:
The fan should be connected to a Trinary switch connected to the DASH AC system pressure hoses. Once the Dash AC pressure reaches a certain pressure, the Fan relay closes and runs the fan. Being 2o years old points to a bad fan also. I would disconnect the quick connect on top the fan and jump 12 volts pos and neg to the fan to see if it actually runs. Then start your diag if it DOES run. Doug

If the pressure switch/es are not working would not the A/C function as well?

Used some jumper leads from the battery to the fan connector and the fan does not run off the battery.

Also changed both the lower and upper radiator hoses (Continental) and T-stat (195 AC Delco). That upper hose was a bear to reach and one would never be able to get it out with the cruise control box mounted on the frame. Had to move it out of the way.

Fan in question:

https://www.dropbox.com/s/oilh4kcssl2dkcn/IMG_0411%5B1%5D.JPG?dl=0

The relay for the fan?

https://www.dropbox.com/s/e78a5103ygrztya/20180513_032855%5B1%5D.jpg?dl=0

From Chevy P30 Motorhome chassis service guide https://www.gmcmi.com/wp-content/upl...sis-Manual.pdf

Under Appendix 2-1 Optional Air Conditioning System...(Figure A2-1-7 Typical ARA Wiring Diagram - Class "A" RV Condenser with Fans) p.2-12

It shows the temp sender switch is normally open, closes to ground at 221F approximately.

NOTE: Starting with the 1991 Class A motorhome, the A/C condenser fan is wired by Chevrolet through the main front end engine wiring harness . The coolant temperature switch is now located in the RH cylinder head with a green wire.


It appears that the electric fan on the front of the A/C condenser should only come on after the relay closes (approx 221F) with the A/C on.

Anyone know how to confirm whether or not the coolant temp sender on the right side manifold is working correctly? Any ideas as to what the resistance value/s should be?

dougrainer wrote:
The fan should be connected to a Trinary switch connected to the DASH AC system pressure hoses. Once the Dash AC pressure reaches a certain pressure, the Fan relay closes and runs the fan. Being 2o years old points to a bad fan also. I would disconnect the quick connect on top the fan and jump 12 volts pos and neg to the fan to see if it actually runs. Then start your diag if it DOES run. Doug

The A/C pressure switch is just behind the overflow bottle in the pic I linked to. Will use some jumper wires to check the fan and report back. The A/C does work very well but I just do not recall seeing the fan on when the A/C is turned on.

The fan should be connected to a Trinary switch connected to the DASH AC system pressure hoses. Once the Dash AC pressure reaches a certain pressure, the Fan relay closes and runs the fan. Being 2o years old points to a bad fan also. I would disconnect the quick connect on top the fan and jump 12 volts pos and neg to the fan to see if it actually runs. Then start your diag if it DOES run. Doug

77rollalong wrote:

udidwht wrote:
I have a 1994 Fleetwood Southwind Storm 28ft with a 454 TBI (4L80E) and I'd like to confirm the fan (1) that is mounted on the front of the A/C condenser is working or or not. I don't recall ever seeing it on.

I've heard conflicting ideas of when it actually comes on such as...

Will come on when A/C and engine temp is roughly 220 or so.

Will come on anytime the A/C is on regardless of engine temp. (Haven't seen this myself).

So which is it? And what would be the easiest method of ensuring the fan is working correctly. I know it's tied into the PCM and the passenger side sensor (cylinder head) and possibly the A/C pressure switch.

Picture of my fan...
https://www.dropbox.com/s/oilh4kcssl2dkcn/IMG_0411%5B1%5D.JPG?dl=0

1994 Fleetwood Southwind Storm Chevy P-30 28ft 4L80E 454TBI
VIN#1GBJP37N4R3314754
56,139 US miles

you are correct, it should come on when the AC is turned on independent of the engine temp, you may have a 2 speed fan as well, check the fuse box under the hood, and see if there is 2 coolant fan relays in the box, i had a test relay that had a switch so i could just remove a relay, and plug in a test relay and turn on and off what ever i need to , there should be a fan Fuse also in the same fuse box...

Under the hood? You mean under the dash?

udidwht wrote:
I have a 1994 Fleetwood Southwind Storm 28ft with a 454 TBI (4L80E) and I'd like to confirm the fan (1) that is mounted on the front of the A/C condenser is working or or not. I don't recall ever seeing it on.

I've heard conflicting ideas of when it actually comes on such as...

Will come on when A/C and engine temp is roughly 220 or so.

Will come on anytime the A/C is on regardless of engine temp. (Haven't seen this myself).

So which is it? And what would be the easiest method of ensuring the fan is working correctly. I know it's tied into the PCM and the passenger side sensor (cylinder head) and possibly the A/C pressure switch.

Picture of my fan...
https://www.dropbox.com/s/oilh4kcssl2dkcn/IMG_0411%5B1%5D.JPG?dl=0

1994 Fleetwood Southwind Storm Chevy P-30 28ft 4L80E 454TBI
VIN#1GBJP37N4R3314754
56,139 US miles

you are correct, it should come on when the AC is turned on independent of the engine temp, you may have a 2 speed fan as well, check the fuse box under the hood, and see if there is 2 coolant fan relays in the box, i had a test relay that had a switch so i could just remove a relay, and plug in a test relay and turn on and off what ever i need to , there should be a fan Fuse also in the same fuse box...

I believe that fan is for your radiator and it should come on when the water temperature reaches a set amount. Connect the fan directly to 12 volts. If it does not work replace the fan. If it does work trace the circuit back to find the fault.