alabama

has any one out there currently experiencing or in the past the following? during acceleration the air conditioning will go to heat mode. once the accelerator ls leveled off it goes back to the ac mode. something is letting the blend door vacuum to move it to the heat mode. i can't find it. driving me crazy. can anyone help???? thanks go bama

johnh

the vacuum is dependent on the vacuum pump, so i can't see how acceleration would affect any vacuum controlled systems keep looking...i guess it's possible the pump is going out

alabama

thanks for the reply. i thought of that also however it will happen on the highway with the cruise control on, and during acceleration up a hill it will do it and it doesn't affect the cruise control that is vaccuum controlled

BigIron70

Try installing check valve in vac hose to ac control.

alabama

thanks i'll give it a try

high bid

What did you find....I have a similar issue where it will be cold a/c and then flop you hear a sound like the blend door closing and it's almost instantly hot air.

mrclean

The blend door is electrically operated, not by vacuum.....
There is an electric actuator on the bottom of the HVAC case in the passenger-side footwell. There is a plastic connector piece that attaches the actuator to the blend door......this has likely broken, letting the door move on it's own. www.heatertreater.net

whiskers

I had the same problem and searched from one side to the other of the engine bay with no luck. But as I fooled around with a perfectly good looking vacuum line, the one that goes across the top of the cowling, it came apart and I found the culprit. Looked perfect to the eye, but a little tug it came apart. it was a hard plastic hose i never suspected. it was completely in half but you couldn't see it. Put a little flexible line in fore a connecter between the two pieces and all is good in my world now !!!