AC quits after 30 minutes

[Lenny]

It's getting warm in Florida. I drove for about 1/2 hour and the AC was nice and cold but then it just stopped. I turned it off and about 10 minutes later turned it back on and it worked fine till I got home. Took it out for a wash and final prep for Celebration next week. On the way home, after 10 minutes of drving it quit again. Same thing as before 10 minutes later I turned it back on and it worked fine till I got home.

Any ideas?

[Bitsyncmaster]

When it stops, is the compressor turning?

[David T]

When it stops, is the compressor turning?

Just exactly what do you mean by "It Stops"? Is the heater fan still running? Is it running but no longer blowing cold air? Is the compressor still cycling? When it IS running is it "making water"?

[Lenny]

When it stops, is the compressor turning?

I think so but not sure I'll listen. But, the fan stops. I turned it to Vent and the fan would not work there either.

[Soundkillr]

Sounds like you need new blower speed relays. Try going to the lower fan speed setting when it happens (if on high setting) or vice versa. It may be that just one is overheating.... Two relays for setting 1/2 and 3/4

[Rich]

Sounds like you need new blower speed relays. Try going to the lower fan speed setting when it happens (if on high setting) or vice versa. It may be that just one is overheating.... Two relays for setting 1/2 and 3/4

Close on that one.

No relays on fan speeds 1 and 2.

One relay for fan speed 3. Separate relay for speed 4.

One circuit breaker feeds both the Speed 3 relay and the Speed 4 relay.

So next time it happens the PO can check which fan speeds are cutting out. And whether they ever come back on...

Reference: LINK: http://dmctalk.org....-All-Wiring-Schematics (http://dmctalk.org/showthread.php?40-All-Wiring-Schematics)

[Soundkillr]

Thanks for clearing that up Rich. Hopefully that's all that is wrong with is car....

[sdg3205]

Just had a fellow owner in Florida ask me about this exact same issue today.

His compressor and AC fans continue normally but the HVAC blower became intermittent. I've sent over the schematics. My guess is the circuit breaker. I've seen them get so hot they burn your hands. Once cool they seem to work again, which begs the question - is it higher resistance (bad ground?) that is leading to the trip, a soon to die blower motor pulling more than 30 amps, or local temperatures aggravating a problem? The relays for 3 and 4 may have some corrosion. Something somewhere is causing higher current draw.

[David T]

Just had a fellow owner in Florida ask me about this exact same issue today.

His compressor and AC fans continue normally but the HVAC blower became intermittent. I've sent over the schematics. My guess is the circuit breaker. I've seen them get so hot they burn your hands. Once cool they seem to work again, which begs the question - is it higher resistance (bad ground?) that is leading to the trip, a soon to die blower motor pulling more than 30 amps, or local temperatures aggravating a problem? The relays for 3 and 4 may have some corrosion. Something somewhere is causing higher current draw.

Check and see if you have the uprated circuit breakers which would be the relay upgrade kit for the cooing fans and the heater fan. If the blower stops and then starts again it is either the circuit breaker or a bad fan motor drawing too much current (or possibly both).

[DMCMW Dave]

Just had a fellow owner in Florida ask me about this exact same issue today.

His compressor and AC fans continue normally but the HVAC blower became intermittent. I've sent over the schematics. My guess is the circuit breaker. I've seen them get so hot they burn your hands. Once cool they seem to work again, which begs the question - is it higher resistance (bad ground?) that is leading to the trip, a soon to die blower motor pulling more than 30 amps, or local temperatures aggravating a problem? The relays for 3 and 4 may have some corrosion. Something somewhere is causing higher current draw.

All of the above, but bad connections will run hot and trip the breaker even at current below spec. Unless you are a super-purist, replace the breakers with stud-type breakers, cut the factory connectors off and use crimp-on ring lugs. They will run a lot cooler.

BTW - corrosion does NOT increase current draw in a circuit, in fact it lowers the current flow as it is a higher resistance. Look up Ohms law. It does however cause heat at the point of corrosion. If that happens to be on a thermal-trip breaker, it will trip early.

[sdg3205]

Dave t - it's the Dmc purple update.

Dave s - thank you for the clarification.

[David T]

Dave t - it's the Dmc purple update.

Dave s - thank you for the clarification.

Not sure what the "purple update" means. Check the ratings on the circuit breakers.

[sdg3205]

Not sure what the "purple update" means. Check the ratings on the circuit breakers.

That means it's the expensive update kit.

[Chris4099]

Regarding the breaker, make sure it's 30 amp, not the original 25 amp. Next, verify the wiring is the correct polarity. I'm not sure what happens if they are wired backwards, but they are polarity specific for a reason. All this is assuming that the next time this happens, moving the fan switch to 1 or 2 suddenly fixes the problem (as you are now using a fuse and not the circuit breaker).