Thread: Air con wiring advice needed?

Does anyone know an air con guy around the bayside / Carindale / Wishart / Cannon Hill area of Brisbane. Someone knows LR preferably

Originally Posted by brett43au

Hi Im alos having problems with the air con in a 97 defender . It looks simple enough with all the wiring going back to a set of realys and a black box in the battery well . I cant get power at the compressor clutch . Solenoids seem to click as does the large black box in the battery box fuses all look OK . What did you serach on the find the wiring diagram as I have tried a few serches and cant find it .
Rgds Brett

that will usually be a burnt relay seat or contact if your lucky and the compressor clutch wires/plug if your not.

Fender 22, I'm 50 Km away if that counts as close.

Here is the cct diag.

If unclear, here is a rough legend
Resistor: top left
Blower switch: below resistor
Blower motor: to right of resistor
Thermo Switch below Blower motor
Temp Probe: to right of Thermo Switch
Compressor clutch: half way down on right
Pressure switch: to left of clutch
Relay: to left of Thermo-Amp
Double rectangles are the inline connectors
Thermo-Amp: rectangle with 8 leads

Top dotted line is all inside internal aircon unit

Bottom dotted line should be in battery compartment.

Operation:

12v is provided via relay from ignition switched source.
Thermo-amp is powered once blower switch set at 1 to 3.
Temp Probe sends signal to thermo amp which compares with internal reference and Thermo rotary switch position.
12v supplied to compressor clutch if probe temperature higher than thermo-amp result.
cooling via evaporator/compressor/condenser plumbing.
Once probe signal reaches desired value, Thermo-amp shuts of compressor.
The pressure switch can differ between installations as some have a high/low pressure switch.

If temp of refrigerant gas gets too high, pressure increases beyond threshold of pressure switch and cuts power to compressor. If refrigerant gas leaks, pressure is then to low and switch cuts supply to compressor.

If single switch, If pressure too high then compressor power is cut.

Suggested mods.

Fit trinary switch to receiver/drier and fit electric fan in front of condensor. run the fan through a relay switched by trinary switch high pressure wires and series up the low pressure wires to the compressor (this will ensure you don't run the compressor without refrigerant).

Remove and drill/tap blank hole in thermostat housing and fit normally closed temp cutout switch to over ride pressure switch. This will shut a/c off if engine temp climbs above threshold of temp switch. If you want to go a little further, drill/tap other blank hole and fit normally open temp switch and feed in parallel to relay that drives fan. This will allow you to have additional forced air through radiator, especially when off-road or in heavy stop start traffic.

Both these temp switches are standard in the disco 300tdi a/c system.

Hope this all helps

Tony
photo.jpg

Really appreciate your trouble mate. I have a 200TDI defender. Would the wiring diagram be the same?

I found this copy in 'the good oil'
http://p38arover.com/rover/defender/...20Defender.gif
Thanks to Ron AKA p38arover
Don

Originally Posted by fender22

Does anyone know an air con guy around the bayside / Carindale / Wishart / Cannon Hill area of Brisbane. Someone knows LR preferably

Yes, see here for details at end of post TDI Defender Air conditioning Fixed

K2 Air con is the guy I have looking at mine on Wednesday! How lucky is that.
I asked him if he knew LR and he just said yes. I thought to myself sure...

You can use a manual thermostat with a capiliary tube to set the temp instead of the thermo amp. Any A/C service guy can fit this.