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Rear heat issue -- new parts

Posted: Tue Jan 30, 2018 1:09 am
by SteveTR6
2003 Astro AWD LT, 156k miles. Within the last 2 weeks, the blower resistor failed, followed (almost immediately after replacement) by the blower motor. Fixed all that, now have perfect heat again in front. For the last few months, the rear heat has not worked. I bypassed the solenoid by routing the manifold (incoming) vacuum hose directly to the heater valve, which worked for a while until the valve failed and started puking coolant. Last week I replaced both the solenoid and the valve with new parts. After install, I get no hot air to the rear. I let the thing run for a loooong time (also driven it 50+ miles), made sure the coolant was full, everything. Front blows burning hot air, rear about 70 degrees. Today, I decided to pull the manifold vacuum line off the solenoid to make sure it's not plugged with coolant from when the valve failed. As soon as I pull the hose, I hear it hissing (good!) and the rear starts blowing hot air. Now I think I messed up somehow.
Can somebody please tell me the CORRECT way to hook up the vacuum lines? As in, how did Chevy do it? I installed the manifold vacuum tube to the top nipple on the new solenoid, and the bottom nipple I connected to the nipple on the valve. Obviously, that's not right....
Thanks
Steve

Re: Rear heat issue -- new parts

Posted: Wed Jan 31, 2018 2:16 am
by Captn. Crunch
You’re asking a question conserning just about the only thing on my van I haven’t had my hands on. Hopefully someone who has will be by to help. I’d go look at mine but it dark and snowing