Well, the 1 tonner aircon story continues...and it’s got a crazy twist! Read on if you dare!

Prologue.
I recently noticed a small noise coming from the sexy new A/C compressor at around 1200rpm, so took it back to Dandenong Radiators for a peep, where they identified a mild harmonic whine coming from the front clutch assembly at 1200rpm. No biggy as it was making cold air, so we accepted all was well and carried on. Couple of days later I get a call from Dandy Rads with an update, you see the little noise had been bothering the boss and he followed up with the supplier and long story short, I got the deal of the century! A completely new modern Sanden changeover compressor with new brackets for bugger all cash, what could I say? Hmm....

Episode 1
Dropped back in for the changeover on Wednesday and all seemed to go well. Degassed the system, swapped out the compressor and brackets, vacced it down and poured the R134a gas back in. All good so far and the system fired up well. It even gave the 308 around 100HP back as it didn't have to drive the heavy AC Delco replica and the Sanden looked a treat. I noticed storm clouds gathering on the Melbourne horizon and didn't realize they were meant for me!

Episode 2
Went for a drive later that day and as the Melbourne weather was pretty much a Broome wet season, I fired up the A/C and settled in for a frigid drive, expecting cab temperature to be colder than a mother in laws kiss...then it all went wrong. First sign of trouble was a decidedly less than freezing experience and as the cab temp climbed to central Australia temperatures, I jumped on the blower to Dandy Rads (thanks Android Auto). As I was describing the symptoms over the phone, disaster struck! Everything suddenly turned off, I mean completely, fan and all! Noooooo!!!! I was told over the phone to keep my cool, open the windows like every other old Holden driver and drop back in the morning for a check-up.

Episode 3
As the mini Melbourne wet season continued its build up yesterday, we were back at the shop diagnosing the system and after some back and forth, it was discovered that a circuit breaker was tripping when the auxiliary thermo fans and compressor were running together, WTF? So off I went to ponder life and electrons. Compounding issues was the sudden tropical downpour across Melbourne which wiped out all visibility and steamed up my windscreen, if only I had A/C!!!!!

Episode 4
Back at base camp in my trusty garage, I dug out the WB electrical diagrams and poured through the Caprice wiring, looking for a reason to trip circuit breakers…and then I found it. What an epic blunder by Holden! Couldn’t believe my eyes and even questioned my electrical skills for some time, before manning up, realised I’m still the world’s greatest electrician and called it what it was, a right royal fuck up! You see, the electrical circuit driving the auxiliary fans on the front condenser, has a trusty relay in the engine bay, so the control circuit for A/C doesn’t have to handle heavy motor current. HOLDEN WIRED IT UP ARSE ABOUT! OMG! The fused aux fan (load) wire running from the alternator to the relay was connected to the relay coil terminal and the control wire for the coil was connected to the power terminal (30). The Holden service manual even shows the arse about wiring in the circuit diagram! I swapped the wires back over and hey presto, everything works again.

Wow, what a find. Unbelievably the arse about wiring actually works for a bit but I guess the extra current soon trips the circuit breaker, and being a resettable bimetallic strip breaker, it will generally reset itself so the issue may be masked indefinitely. So why didn’t I noticed it with the other compressor? Well the thermo fans rely on an extra switch in the radiator to turn on the relay when temp gets over 95 degrees and my new Sanden compressor setup is rigged so the fans are on all the time when running A/C. This compounded the wiring mistake and tripped the breaker.

Hope this story was fun, it’s fun for me but only now that I know what’s going on….