Chevy & GMC Vans

I've been reading threads and trying to narrow down my issue, and I'm not having much luck. I have a feeling I could replace several more parts before I hit the nail on the head...

My blower only works on high, which is fine with me for now, if it's a seperate problem.

At first, I had warm air- not hot. Would let the van cool overnight, in the morning when I'd fire it back up- no heat. NONE. Go out at lunch, heat would resume.

Have already replaced thermostat.

Now, it's gotten warm outside...I decided to try out the AC- which seems to work nicely. Except now it won't turn off. Can't get my heat to kick on even intermittently at this point, and can't get the AC to turn off.

What do you guys think my first plan of attack should be? My husband said when he replaced the thermostat that he thought the coolant was flowing just fine, but I know he's not opened it back up since to check my levels either. Wondering if I could have had a big air bubble that's cleared out and I'm low. But would that explain why my AC seems to be stuck on... what part is responsible for deciding heat/outside air/AC?

Really appreciate the wisdom guys.

The hot/cold laziness is most likely a vacuum leak or it's the electric blend door actuator. The fan speed speed issue is due to the resister pack I think.
viewtopic.php?f=39&t=5345

Please put your vehicle details in your signature.

Hey Doris, add your van info to your signature line so we know what you have.

TLB is most likely right on the fan speed. Depending on what year your van is, the resistor pack could be separate from the high speed relay.

As for the heat/no heat issue, with the selector on high temp and the fan on high, feel the hoses going into the heater core. These are located on the passenger side going from the engine to the firewall area. If they are cold, you are not getting flow.

Thank you! I did print off a good thread with some troubleshooting ideas regarding the hoses to help narrow it down, will try that tonight.

And I'm sorry about my signature...I've not yet figured out how to change that part of my profile. Will work on it!

Have a 1999 2WD astro conversion.

Alright- so AC's been stuck on for two days in 80 degree weather, even though I had the switches pointing to defrost and the heat all the way up. After driving for about 30 minutes last night, I rounded the corner into my neighborhood and BAM- heat kicked on, hotter than the blazes of hell. So weird. I didn't touch a thing, and this morning- still had heat.

I suspect low coolant level then.

Jim

Now, wouldn't that be nice!!! Easy fix. I just need to remember to check in when the van's warmed up.

Becareful of a warm/hot check.

I would check it cold, first thing in the morning over a period of a few days.

Good Luck, Jim