70sgeek

basically a question for anyone with Vintage Air Gen IV ac install experience - after a recent engine swap the compressor on my Vintage Air system won't power up - the ac control panel (blower/temp controls) works properly but doesn't trigger the compressor - it is charged but still no power coming into it from the under-hood dark blue binary switch wire connected to the compressor power lead. I did jump the compressor to another 12v+ lead - by that means it works and blows cold air into the vents, so appears to be something inline with the system wiring - maybe the blower box relay under dash?

I know the 2-prong binary switch cuts power to the compressor if insufficiently charged (or over-charged) but my low side gauge shows just shy of the green after a recharge of 2 cans of 134a (approx 24oz), so i hesitate to put any more in yet if refrigerant charge isn't the issue.

All previously worked perfectly before the swap, which didn't involve any physical disassembly of the ac components from the engine bay.

The firewall-mounted circuit breaker is showing full battery power, so no apparent issue there. The 2 white blower box ground leads coming thru firewall into engine bay are properly grounded. I have an email into VA seeking their input but figured I'd post here as well for any more immediate education which might be available.

thanks

Loaded68W34

Did you check for power going into the binary switch from the A/C control, or did you only check for power coming out of the switch to the compressor? If you have power going into the switch when the system is on, the problem is with the switch, the refrigerant charge, or wiring between the switch and compressor. If there is no power going into the switch, start tracing for power back to the relay/ control to find the problem. The gen IV is designed to run on 1.8 lbs of 134a. That is 28.8 ounces. I would think 24 should be enough to trip the bianary. However, if you have power going into the switch and not coming out, I would start by adding more refrigerant.

70sgeek

Appreciate the prompt reply!

There is 12v showing at the light blue-wired binary switch terminal (feeds out from the dash unit) but not the terminal connected to the dark blue-wire (which plugs from switch to the compressor (+) wire.

So there does appear to be power feeding upstream from control panel to switch, just not downstream from dark blue-wired terminal to compressor.

The dark blue wire is essentially just a short length jumper from switch to compressor, so I'll probably make another one for good measure.

In the short run barring any connectivity change, off to Walmart for more refrigerant .

joe_padavano

If the switch isn't closing, why do you think you need to replace the wire?

70sgeek

You are likely correct. I probably don’t. The ac installer spliced an idle solenoid wire into it. Maybe the splice came loose during engine swap causing a disconnect point. But i doubt it so ill try a bit more refrigerant first to see if it solves

70sgeek

So after a bit more troubleshooting with VA assistance, still no compressor power coming in from binary switch.

At their direction, I pressurized the system to approximately 35psi to ensure enough that should definitely have caused the switch to trigger the compressor, but no go. As before, compressor worked fine on a jumper (+).

Even as it does have power feeding in from the blower box, the VA rep believes it may be a bad binary switch not reading the system pressure, so they're sending me a replacement VA tech support is exceptionally helpful and hopefully with a new switch installed I'll be back online.

joe_padavano

If you have power into the switch and no power out of the switch, there are only two possible causes - low freon charge or bad switch. Since you've eliminated that low freon as a possible cause, there's only one option left.

70sgeek

Hopefully a new switch will solve this - FL summer heat w/o AC = !!

joe_padavano

To confirm, you did jumper across the terminals in the switch connector and got the compressor to work, right?

70sgeek

Finally had recent opportunity for the new VA binary switch install and that apparently was the problem, in large part if not in full.

System back to proper working order and blew 40* upon recharge. Leak test performed indicated no issues, so hopefully I'll get thru at least the upcoming FL summer without further drama.