I do not get a vacuum signal to reach a new heater control valve.

Hence, hot engine coolant continuously enters the passenger interior and heats the passenger interior on hot days.

Can anyone shed light as to the vacuum source?
I figured that sliding the dashboard temp control lever from side to side or depressing the A/C button may/should trigger some vacuum action at the heater control valve.

Neither of these actions have made vacuum appear at the heater control valve.
In the meantime, I pinched off the heater hose to stop hot coolant from entering the cabin heater core area.

I cannot find a reference text on this subject.
The Haynes 1988-1993 Repair Manual appears to be silent on this subject.
Is there a connection between the dash temperature control panel and a vacuum source?

 

I know nothing of these cars, but the heater valve HAS to be hooked to the dash control. It may also go through the temp control lever / **** if that is physically separate

Heck, LOL this time of year you are probably about ready for heat again?

 

I found a photo of the heater and A/C Temperature Control Switch on eBay and it shows several colored vacuum hoses exiting the rear of the control switch . I guess that the vacuum hoses will control the blend door and will control the heater vacuum switch in the engine bay .
I do not have knowledge of the OEM setup / function.
can anyone shed light on the 9 vacuum hoses that enter/ exit the back of the Temperature Control Switch ?
The vacuum hoses in the eBay photo are light green, dark green , two yellow, two red , brown ,2 black .

 

You need to get yourself a factory service manual

 

I tried to find it for you on my Mitchell Pro demand and it did not list a Under dash Vacuum Diagram... Sorry no help here..

 

I found one in Alldata... I'll try to get it up loaded for you....

 

 

My air in my 98 Van has never worked properly. Not worth the effort - need to take the complete dash apart..
Is yours R12 or R134a ????

 

Oh Come on Lynn.... Pull the windsheild out and get that Bit&% pulled apart and get it retroed to R134... The older we get the more we need Air.....

Like I'm One to talk... I have never had air in my truck... My Warlock never came with it.... Cant be spoiling the Rednecks.....

 

98 is factory R134 already Just bought a case of 12 from ebay $70. Hard to get anything in Ca. All they want to sell you are the big 24 oz ? bottle kits for $40.
Had to put a can of R12 in my daily driver 88 olds quad 4. Hay it was free !!!! has 136K

 

Cant go wrong with that...

 

Racerhog- thank you for the upload . I have been away from the forum and missed your posting. Much appreciated.

 

Hope you got it fixed !!!!