Iacovetti

I have a 88 IROC-Z with a tpi 350..
There is a vaccum line from the top of the heater control valve that goes into a wire loom and through the firewall to *** knows where??? The thin plastic line is broken deep into the harness, I cant find it in the harness because there is no room to put my hands in there. What I am experiancing is this... When I turn the heat on Cool air blowing like defroster , Will not blow hot air at all or on floor and not through vents. My question is this...

How can I FRESHLY run a completely new line from heater control valve and where does it actually go to? I pulled my heater controls out of my car and didnt see a thin plastic line anywhere to tap into.
Please help me find this mystery plastic line!!!
I would be very grateful!!!!
Chris

Vader

You might actually need to find the far end of the purple line. This may help:

Vader

Incidentally, Welcome Aboard!

Iacovetti

On the heater/ac control unit there is 3 vacuum line connector 2 purples into a Y and then there is a grey Those go from the back of the heater/ac control unit to up under the dash somewhere, I am sorry if a little confused...
Where does the vacuum line from the heater control valve end up at? OR where does the purple "y" line and grey line on the connector from the heater/ac unit go to?

Thank you!
Chris

Kaps

just wondering if you found the problem, as I have had that problem for months now, but its starting to get cold. I know I tried checking the vacuum lines inside the engine bay but cant seem to figure out where exactly the line I need goes to. Vader tried helping me a while ago, but I didnt want to be a pain in the ***, lol. Any help is greatly appreciated!!:hail:

novass

iTrader: (1)

That line goes thru the fire wall and connects to the heater valve which is connected to the top line off the heaer core and connected to 2 other hoses. located above the front passenger side valve cover.

I have attached a picture...arrows point to the vaccum line circled is the heater valve diverter.

Ps. Doesn't matter if it is a tbi or tpi engine

novass

iTrader: (1)

oops: image

novass

iTrader: (1)

If worse comes to worse, for the winter you could connect the line directly from the heater core to the fluid flow path and it would give you heat. (by removing the diverter and bypassing it)

Kaps

Thanks, my hcv was put in upside down, so when I unhook the vac line, I now get heat. While I was out I ripped out the hvac controls, radio and half console to look for vac lines, all I found was wiring, all the way back untill it hit the core box. Its an 88 gta. My vents are all barely getting air so when I searched it said vac lines, cant find any. If this helps I have what seems to be a broken black plastic vac line to the left of the firewall from the hcv line in the engine bay. Cant seem to see where it should go. Any help once agin is appreciated, and thanks for helping!!

edit: also the blower doesnt work on high, and now low doesnt work either just the 2 in the middle...

TomP

Bah; just dump that rotten heater control valve out of the system. The things get brittle after a few years and snap. I unfortunately put the whammy on one guy's valve... a little informal meeting of the NorthEast guys in Jersey- he had a leak at his heater control valve, and as I was saying how brittle they get and how I'm glad my '86 doesn't have one, it snapped on him as he tightened a hose clamp. Man, I felt guilty.

Iacovetti

I read all of the replies. I need that small thin vacuum line because I have no control where my heater blows, I can select vent or heater, It only blow a little on the defrost, Also there is no heat it blows cold air, I have a 160 degree thermostat in it because of the hypertech thermomaster chip, My car runs NO HOTTER than 160-170 degrees, I flushed the cooling system to check for a blockage in the heater core and nothing , I am really starting to get pi$$ed off with this heating system in this car, Of course in cold a$$ chicago you need the heat. That you very much for all of the replies and I please hope to get more .
Chris

377Z

iTrader: (1)

Just fixed the same problem on my 91 T/A.

Look in the area under the carpet on the driver's side above the gas pedal/behind the radio. There you should find a connection that has a purple line and a grey line connecting to the thin black lines. From there the thin black lines go over the hump to the passenger side, through the firewall, and into the engine bay. The purple controls the air distribution, the grey controls the hcv.

I removed the hcv on my T/A and connected the other black line meant for the hcv to the purple line in the car (don't forget to connect the other end in the engine compartment to vacuum). Now the distribution works properly & I didn't have to worry about running new vac lines through the firewall.

The hcv is a thorn in the *** of thirdgen owners. All it does is keep hot coolant from circulating through the heater core when the heat is not on. Sounds great on paper, but it adds needless complexity to the engine compartment (via extra hoses and the damn hcv), and probably contributes to earlier heater core failure because of no circulation. Some people think if you remove the hcv your ac will be hot; thats a retarded thing to think because there is a door connected to the temp control & if you select cool air it will not go thru the heater core. It might heat the surrounding area a bit but a few who have removed it and have working a/c commented that they noticed NO difference in a/c effectiveness (I can't say, my a/c needs service & won't get it until next summer).

Don't know about the fan speed problem but would guess its the switch; since you live in Chicagoland maybe you could try getting a spare at Pick'n'Pull in Summit, they have reasonable prices.