Decided to tackle the air con & oil cooler, ballast resistor replacement. I was keen to try the fix as detailed on RennList as it looks as though this will be a life-of-the-car-fix.
Briefly each side consists of:
Heatsinks made from angle aluminium: 4" x 1 ¼" x 1 ¼" x 1/8";
2 power resistors 50w 1 ohm;
1 thermal switch, 70c 50c reset;
Heat sink compound;
6 x M3 6mm machine screws.
You'll also need connectors; crimp-pliers; suitable wire; heat-shrink; hot air source for heat shrink; 2.5 mm & 8.5mm drill; & M3 taps.
Further details here:
http://forums.rennlist.com/rennforu...and-ac-fan-low-speed-resistor-redesigned.html
http://forums.rennlist.com/rennforu...sistors-oil-and-ac-low-speed-redesign-ii.html
First thing was to determine whether the resistors were working or not & ensure the fans worked. Fuse/relay box cover off & identified relays R04 (oil cooler fan) & R14 (A/C condenser fan).
Caution: Keep in mind the relay terminals are energized 12v at terminal 3(30) even with the ignition off.
-Remove relay R04 (oil cooler blower).
-Jump terminals 3(30) & 7(87c) for slow speed. Fan should run, even with the ignition off. If the fan runs in slow speed, your ballast resistor should be okay.
-Jump terminals 3(30) & 5(87) for fast speed. Fan should run, even with the ignition off.
You can check the A/C condenser fan similarly, removing relay R14.
My fans worked on high speed OK but were dead at slow speed.
Jacked the front of the car up & removed the front section of the wheel arch liners. Starting with the A/C (LHS) side I discovered how bad that resister was. The leads fell out (lucky it hadn't shorted out!) & the ceramic crumbled away. The date said 96/01 so maybe this is the original? The bolt was well rusted in so I left the remnants behind, as it didn't get in the way.
Made up the resistor package & bolted to the frame. The cut off fly-lead from the dead resistor was used to connect up to the plug. Tested at R14 & the fan now works in high & low speed.
Similar on the other side, but because the resistor is mounted well forward it's impossible to access without removing the front bumper cover. Identified the wire & gave it a pull to disconnect the plug. The plug was cut off & the resistor package bolted to the frame & connected to the wiring with spade connectors. Tested at R04 & this fan also works in high & low speed.
The resistors do warm up in use but as they are wired in parallel the two 1 ohm resistors give an overall 0.5 ohm resistance but with double the power capacity of the OE. I tested them for 5 minutes on slow speed. I could touch the resistors for a few moments but the heat sinks were doing their job well as they were only warm to the touch. If they did overheat, or there was some internal failure, the thermal switch would cut the power at 70c. The resistors are also mounted in an air stream so should be sufficiently cooled whilst the car is moving.
Briefly each side consists of:
Heatsinks made from angle aluminium: 4" x 1 ¼" x 1 ¼" x 1/8";
2 power resistors 50w 1 ohm;
1 thermal switch, 70c 50c reset;
Heat sink compound;
6 x M3 6mm machine screws.
You'll also need connectors; crimp-pliers; suitable wire; heat-shrink; hot air source for heat shrink; 2.5 mm & 8.5mm drill; & M3 taps.
Further details here:
http://forums.rennlist.com/rennforu...and-ac-fan-low-speed-resistor-redesigned.html
http://forums.rennlist.com/rennforu...sistors-oil-and-ac-low-speed-redesign-ii.html
First thing was to determine whether the resistors were working or not & ensure the fans worked. Fuse/relay box cover off & identified relays R04 (oil cooler fan) & R14 (A/C condenser fan).
Caution: Keep in mind the relay terminals are energized 12v at terminal 3(30) even with the ignition off.
-Remove relay R04 (oil cooler blower).
-Jump terminals 3(30) & 7(87c) for slow speed. Fan should run, even with the ignition off. If the fan runs in slow speed, your ballast resistor should be okay.
-Jump terminals 3(30) & 5(87) for fast speed. Fan should run, even with the ignition off.
You can check the A/C condenser fan similarly, removing relay R14.
My fans worked on high speed OK but were dead at slow speed.
Jacked the front of the car up & removed the front section of the wheel arch liners. Starting with the A/C (LHS) side I discovered how bad that resister was. The leads fell out (lucky it hadn't shorted out!) & the ceramic crumbled away. The date said 96/01 so maybe this is the original? The bolt was well rusted in so I left the remnants behind, as it didn't get in the way.
Made up the resistor package & bolted to the frame. The cut off fly-lead from the dead resistor was used to connect up to the plug. Tested at R14 & the fan now works in high & low speed.
Similar on the other side, but because the resistor is mounted well forward it's impossible to access without removing the front bumper cover. Identified the wire & gave it a pull to disconnect the plug. The plug was cut off & the resistor package bolted to the frame & connected to the wiring with spade connectors. Tested at R04 & this fan also works in high & low speed.
The resistors do warm up in use but as they are wired in parallel the two 1 ohm resistors give an overall 0.5 ohm resistance but with double the power capacity of the OE. I tested them for 5 minutes on slow speed. I could touch the resistors for a few moments but the heat sinks were doing their job well as they were only warm to the touch. If they did overheat, or there was some internal failure, the thermal switch would cut the power at 70c. The resistors are also mounted in an air stream so should be sufficiently cooled whilst the car is moving.