Replaced VSV....still no heat!

[Caplax40]

Well I finally received my new (used) heater VSV and promptly replaced it, and of course, I still don't have heat.

What is the next thing to check? Before I lost heat I could push the little bar on whatever the thing is right next to the heater VSV upwards and I would have heat in my car. That only lasted a couple of weeks. Would this be the next logical item to replace and see if that solves it?

Also, just to verify, the longer vacuum hose goes to the nipple on the right of the heater VSV, correct? And the shorter goes to the left? I actually tried switching them up but still produced no heat.

 

[bigunitpitcher22]

I had my thermostat replaced today and my heater started working again. Don't ask me how but it did. Now its nice and warm in my car!

 

[SLO-MK3]

make sure you have all your vacuum hoses hooked up. here's a diagram I found

http://oldschool.supracentral.com/htm/repair.htm#vac

 

[CRE]

I've got the same problem... Does anyone know if this VSV "clicks" when voltage is applied or removed? Neither of mine do. I suspect that perhaps my replacement is also bad. I am getting voltage to mine from the harness, are you?

For the meantime you can just bypass the VSV, you'll have working heat.

 

[jdub]

Well I finally received my new (used) heater VSV and promptly replaced it, and of course, I still don't have heat.

What is the next thing to check? Before I lost heat I could push the little bar on whatever the thing is right next to the heater VSV upwards and I would have heat in my car. That only lasted a couple of weeks. Would this be the next logical item to replace and see if that solves it?

Also, just to verify, the longer vacuum hose goes to the nipple on the right of the heater VSV, correct? And the shorter goes to the left? I actually tried switching them up but still produced no heat.

Since you could push up the actuator bar on the Heater Control Valve and get heat before, I would say it's the control valve itself. Take a look at the diagram...the vac supply line goes to the outer nipple on the VSV, the line to the HCV goes to the inner nipple. You do want to check the vac lines leading to the VSV for good vacuum.

I've got the same problem... Does anyone know if this VSV "clicks" when voltage is applied or removed? Neither of mine do. I suspect that perhaps my replacement is also bad. I am getting voltage to mine from the harness, are you?

For the meantime you can just bypass the VSV, you'll have working heat.

I'm pretty sure the VSV opens (allows vac to the HCV diaphram) when voltage is supplied and is closed otherwise. Simple test...take a piece of vac hose and attach to either nipple and blow through it. Should be no air pass through the other nipple. Take a couple of leads (alligator clips on a length of wire), attach to the battery (correct polarity), and blow through it again. This time air should pass through the other nipple.

If his HCV is stuck shut, the will be no heat unless you run the coolant hose directly to the inlet for the heater core.

 

[CRE]

Yeah, I tried both of them with and without voltage applied. I might just patch in a different VSV for this application.

I've taken a couple of the other VSV's apart, I'm familiar with their construction... too bad they had to go and mold the coil into the housing.

 

[Caplax40]

Since you could push up the actuator bar on the Heater Control Valve and get heat before, I would say it's the control valve itself. Take a look at the diagram...the vac supply line goes to the outer nipple on the VSV, the line to the HCV goes to the inner nipple. You do want to check the vac lines leading to the VSV for good vacuum.

So I take it from your advice I should just replace the CV altogether?


I double checked and I DO have the vacuum lines hooked up properly.

 

[jdub]

So I take it from your advice I should just replace the CV altogether?


I double checked and I DO have the vacuum lines hooked up properly.

Pull the HCV out and take a look at it when you manually move it. Does the valve open? Apply vac to the diaphram actuator and see if that works too.

 

[Caplax40]

Replaced the control valve today along with a different VSV courtesy of tubbie. Same results. Still ice cold air on 85 degree settings. This is frustrating me to no end.

What's the next step?

 

[CRE]

If you bypass the VSV by rerouting the vacuum lines does the control valve open?

 

[Caplax40]

The HCV doesn't seem to want to open. I can still manually push on the thing and get heat but this one snaps shut immediately, where as my old one would sort of stay open for a little while.

One thing I noticed is that both hoses going to and from the HCV are warm, so I don't know if that's any indicator of a different cause of me not having heat.

Any ideas on what to test next?

 

[NewWestSupras]

I wired my "arm" up, and now it works somewhat.

 

[QWIKSTRIKE]

make sure the vacuum lines are not broke, and just run direct vacuum

 

[CRE]

The HCV doesn't seem to want to open. I can still manually push on the thing and get heat but this one snaps shut immediately, where as my old one would sort of stay open for a little while.

One thing I noticed is that both hoses going to and from the HCV are warm, so I don't know if that's any indicator of a different cause of me not having heat.

Any ideas on what to test next?

That would be the diaphram which is bad in your case.