GM Volt Forum banner

2012 no heat...with a twist?.?

737 Views 7 Replies 4 Participants Last post by  tnvolt
The heat in my 2012 went out Sunday night while on a long drive. The i.c.e was running at the time when the heat went out. Monday morning after charging overnight there was no heat in ev mode either. I tried all sorts of button cycling combinations on the climate control screen(changed temp, changed in and out of auto climate, defrost, changed vents, etc) and nothing worked.
The heat icon in the climate control screen would briefly change to "on" then will go to "off" and not come back on at all. AC icon would show "on" as usual.

I jumped online and saw a few threads here and a video about cleaning out the filter in the hose coming from the 2-way valve going to the core.

I cleaned the filter screen today and it was NOT very dirty at all...just a bit of black gunk but I'd say filter was 90+% open to flow.

After reattaching everything I still did not have heat in either for the twist...

With the hood up and i.c.e running I started cycling through the climate control buttons again and after several try's at selecting different modes, temps, etc. I heard a few fairly loud thumps/pops coming from inside the dash behind the climate control screen area. It sounded like a stuck door or flap trying to move(sorta like plastic gears popping). After the loud pops I now have heat with the i.c.e. running but still no heat in ev mode.

I'm not certain if the popping sounds came from inside the cabin or perhaps something attached to the engine bay side of the firewall...perhaps the 2-way valve.??. I'm thinking that maybe the 2-way valve got freed up enough to work briefly after me messing with it when I was cleaning the filter screen.?.?

I went ahead and ordered a new valve this afternoon as it's the next cheapest part to replace anyway and now that I'm familiar with the procedure it will be a relatively easy replacement.

Do you guys think I'm on the right track? Could the thumps/pops be coming from another part of the HVAC system in the dash behind the screen area? The pops were definitely coming from the center area inside the dash/on the firewall.

Thanks in advance for any help and suggestions,
1 - 1 of 1 Posts

· Registered
361 Posts
I hope that it isn't this:
Scroll down to post 18 to see the carnage.
Yours does have a twist in that you now have heat with ICE, even if not battery mode, so your coolant flow valving is still suspect. It's the popping gear / flap open close noise behind the center display that has me worried for you.
1 - 1 of 1 Posts