85.5+ AC fan cycling switch
08-12-2018, 06:33 PM
#1
Intermediate
Thread Starter
85.5+ AC fan cycling switch
Apparently, the 94465305300 fan cycling switch used on my '86 951 is NLA. Has anyone discovered a suitable replacement? Commercial HVAC fan cycling switches are also this 1/4" female flare type. There may be a switch from some other make and model that will work? The factory manuals are no help. I am a 20 year HVAC tech.
Daniel
'86 951
'82 931 (long gone)
Daniel
'86 951
'82 931 (long gone)
Last edited by dvarholy; 03-05-2019 at 08:11 PM.
08-12-2018, 06:45 PM
#2
Burning Brakes
Try
https://plyhammersparts.com
or
https://www.porsche944usedparts.com/apps/webstore/.
They are very reasonable used parts vendors and great guys.
https://plyhammersparts.com
or
https://www.porsche944usedparts.com/apps/webstore/.
They are very reasonable used parts vendors and great guys.
02-27-2019, 09:32 PM
#4
Intermediate
Thread Starter
I ordered the Temp 901409 (which crosses to SW 9052C) fan cycling switch from NAPA. No specifications were listed on their website, so I had to buy it to find out. The closing pressure is 260 psi! This seems rather high for an R12 or even R134a system? Has anyone actually here used this switch? I am afraid of hose/shaft seal/safety valve issues on this 33 year old car? Does anyone know the pressure ratings of the OEM switch?
Daniel
'86 951
'82 931 (long gone)
Daniel
'86 951
'82 931 (long gone)
02-28-2019, 10:11 AM
#5
Drifting
Pardon my ignorance: what is a "condenser fan motor"? By condenser, do you mean the AC "rad" located in front of the regular cooling rad? I don't think the AC condenser has a separate fan?
02-28-2019, 12:06 PM
#6
The condenser "hot" is the rad in the front. The evaporator "cool" is the rad in the firewall plenum thingy bobber.....I removed that assembly on the RAGE2 car recently.
Hence you want to remove the heat from the condenser and air traveling past the evaporator cools down and cools down the cabin.
02-28-2019, 12:12 PM
#7
Drifting
I believe when you turn on the A/C the radiator fans turn on whenever the A/C is running.
The condenser "hot" is the rad in the front. The evaporator "cool" is the rad in the firewall plenum thingy bobber.....I removed that assembly on the RAGE2 car recently.
Hence you want to remove the heat from the condenser and air traveling past the evaporator cools down and cools down the cabin.
The condenser "hot" is the rad in the front. The evaporator "cool" is the rad in the firewall plenum thingy bobber.....I removed that assembly on the RAGE2 car recently.
Hence you want to remove the heat from the condenser and air traveling past the evaporator cools down and cools down the cabin.
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02-28-2019, 01:21 PM
#8
Nordschleife Master
Ok.. so the OP is referring to a switch in the AC system that activates the regular cooling fans in front.. ..and his concern is the one he ordered may wait too long to turn those fans on (the pressure spec)? However, if the rad fans run with the AC on anyway, I assume this extra switch is redundant?
03-01-2019, 12:24 AM
#10
Intermediate
Thread Starter
I will try to find a different switch which is closer to the factory 94465305300 closing pressure of 14 bar (210 psi). The NAPA 901409 switch closes at 18 bar (260 psi). R12 is a relatively low pressure refrigerant not intended for use at such high pressures and temperatures. At 260 psi, the R12 condensing pressure is 160F. Both of these figures are too high for my liking. After looking at various HVAC catalogs of fan cycling switches, I will try Johnson Controls # P100AP-359C which closes at 215 psi and is almost spot on to the original pressure specification.
Daniel
'86 951
'82 931 (long gone)
Daniel
'86 951
'82 931 (long gone)
Last edited by dvarholy; 03-05-2019 at 08:13 PM.
03-01-2019, 01:37 PM
#12
Intermediate
Thread Starter
I have been HVAC tech for many years and have recovery equipment plus a supply of R12. Strange that the manuals say '86 and prior used a temp switch for fan cycling. The pressure switch I am replacing does not appear in the manuals until '87. Everything looks original with no changes to the wiring harness.
Daniel
'86 951
'92 931 (long gone)
Daniel
'86 951
'92 931 (long gone)
03-01-2019, 02:24 PM
#13
Nordschleife Master
Half way through ‘85 is when most things changed, commonly known as 85.5 but I’ve seen it referenced as ‘86 in the Manuals also
’87 was just the offset change to accommodate ABS.
03-01-2019, 06:26 PM
#15
Nordschleife Master