A/C Condensor Fan Operation - Defender Source
Defender Source  

Go Back   Defender Source > Defender & Series Technical Discussions > Defender Technical Discussions

Join the Defender Source Community Today

Thread Tools
Old July 18th, 2006, 08:53 PM
48vphantom's Avatar
Status: Offline
Jeff Hoien
1997 NAS D90
Join Date: Aug 2004
Location: Redmond, WA
Posts: 96
A/C Condensor Fan Operation

Hey everyone Question about your condensor fan operation on the 1997 D90(don't think the 94-95 is the same cause the fan is triggered by the ecu reciving a ground signal, but i could be wrong). I replaced mine because it was frozen up. Now when the a/c is on, according to the wsm, the condensor fan should be running. But if you read the info about the circuit operation thru the trinary switch, it says the contacts close above 305psi on the high side. Trying to figure out if the trinary switch is bad, or if the condensor fan only runs when the vehicle is hot and pressure is really high...I know it is supposed to kick in if the engine overheats. Anyone who would take the time to verify whether their fan runs everytime the a/c is on or just when needed would be appreciated...The fan runs once in a while on mine....

Reply With Quote
Old July 18th, 2006, 09:49 PM
JimC's Avatar
Status: Offline
Jim Cheney
NAS 110 #145
Site Team
Join Date: Sep 2003
Location: Stuttgart, Germany
Posts: 7,115
The fan cycles on and off depending on the pressure in the system and the temperature of the engine. It definitely does not run all the time.

Reply With Quote
Old July 19th, 2006, 08:06 AM
Status: Offline
Arthur Maravelis
97 SW
Join Date: Oct 2003
Location: Boston, MA USA
Posts: 979
In my 97 D90 the AC fan does NOT turn on immediately whenever the compressor engages. The manual says the compressor clutch engages between 35 and 435 psi at the trinary switch. The AC fan engages between 247 and 305 - a much smaller range. Also, fan engages at 225-deg coolant temp and AC turns off at 235-deg.

I'm pretty sure on my 93 LWB the fans engage always with the AC on. ???

I will say that those two RR fans sound very serious compared to the single, whimpy D90. A useful upgrade would be to replace the single with two high flow ones, and run them off the VW switch. These plus your VC fan should be nice.
Reply With Quote
Old July 19th, 2006, 08:29 AM

Posts: n/a
The fan on our '97 D90 does not run constantly when the a/c is switched on, but cycles.

Edit: Oh, the fan does run if the coolant gets hot regardless of the a/c function

The fan in the '94 Disco runs constantly when the a/c is on.

Go figure ...

Reply With Quote
Old July 19th, 2006, 08:46 AM
Status: Offline
Arthur Maravelis
97 SW
Join Date: Oct 2003
Location: Boston, MA USA
Posts: 979
My plan is:

1. add a black box off the temp sender with a pot to select a temp to run the AC fan off of.
2. also feed the AC switch wire so that it comes on when the AC switch is on
3. add a new relay close to the fan
4. remove stock fan relay

This will give you added cooling with the AC fan(s) working directly off the temp sender.

By adding a new relay and the black box you can always disconnect that and reinstall the stock relay and you are back to stock setup.
Reply With Quote

Lower Navigation
Go Back   Defender Source > Defender & Series Technical Discussions > Defender Technical Discussions


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
95 D90- A/C WIRING DIAGRAM (Davia) --> norros Defender Technical Discussions 30 July 7th, 2010 02:38 PM
A/C wiring in 95 jcasteel Defender Technical Discussions 1 August 14th, 2005 05:53 PM
Possible sale of complete A/C Trigger For Sale - Parts 3 June 10th, 2005 01:36 AM
help with a/c motor Campbell Defender Technical Discussions 3 April 12th, 2005 11:25 AM
Pulling out the A/C m.michaels Defender Technical Discussions 5 June 7th, 2004 11:01 AM

» Defender Registry




Add your Defender

All times are GMT -5. The time now is 06:43 PM.