Low coolant? Bad thermostat? Heater core plugged, restricted, or airbound? ============================================================== Good answers by original poster. I would recommend replacing the t-stat first. Its pretty straightforward. If that doesnt solve your problem, our 89 acclaim's have a heater valve (it shuts off coolant flow to the heater core when the a/c is activated to increase the efficiency of the a/c) by the firewall that can stick or lose vacuum (broken vacuum line). Check that next. Lastly, I would take the lines off the heater core and run a garden hose up to it. This will "backflush" any accumulated crud out of the heater core. I do this to my Acclaim every fall and cant believe the crap that comes out! ============================================================== When the heater went out in my car, I went in and found out that it was the heater control valve. Check it out.
evap vacuum cut valve bypass valve
You can find a manual at oriellys called Chilton Chrysler front wheel drive cars 4-cyl !981-95 repair manual
There is no heater control valve on this generation of dodges like there used to be... the water flows constantly through the heater valve.. the only control is a trap door that allows cab air to be run through the heater core and is controlled by a vacuum solenoid in the heater box.. the temp control is also vacuum operated but be sure to check the vacuum supply line coming in from the engine.... it has a check valve in it that can be keeping the controls from getting enough vacuum to operate properly.. if you don't have a mighty vac just get one of those packs of barbed vacuum fittings from your local shucks and bypass the valve temporarily and see if you get heat... hope this helps
It is not adjustable. It is computer controlled. If idle speed is incorrect you have a vacuum leak or a sensor/solenoid issue.It is not adjustable. It is computer controlled. If idle speed is incorrect you have a vacuum leak or a sensor/solenoid issue.
The heater/ac doors are all electric. They are not vacuum controlled.
You can find a vacuum line diagram for a 1993 Plymouth Voyager in the owner's manual. You can also find it at various auto stores.
The heater control valve is used to shut off hot coolant from entering the core when the heater is in the off position. A heater control valve can be actuated by either a vacuum line or a cable from the vacuum heater control valve to the heater core. This hose should be warm; if not the heater control valve is stuck and needs to be replaced
I am not sure what you mean by the radiator bypass. But it sounds like you have a loss of vacuum to your AC/heater control. When you have no vacuum to the control, it defaults to defrost. There is only one vacuum supply entering the passenger compartment through a black hose under the hood on the passengers side close to the AC lines where they go through the dash. There is also a vacuum canister right there. See if you have knocked a vacuum hose off right there.
can happen when vacuum line is disconnected . look under hood to right of heater hoses. one vacuum line goes to heater valve (gate)on heater hose ,the other should go past this to a small sized metal object the size of a small lemon. if this is disconnected only defrost will work. I HOPE YOUR 91 IS SIMILAR TO MY 93.
The heater blend door is not run by vacuum. It is run by an electric actuator.
if im not mistaken the heater control has vacuum lines. take off heater controls and see if you have a bad vacuum line to heater box.
This usually indicates a faulty Evaporative Emission (EVAP) Vacuum Cut Valve/Bypass Valve.1. Verify battery voltage to the EVAP vacuum cut valve bypass valve on the Black/White wire with the key ON.2. Verify the Green/White ground wire for the EVAP vacuum cut valve bypass valve is good all the way to the ECM. The Green/White wire goes to terminal 117 on the ECM.3. Verify the EVAP vacuum cut valve bypass valve is closed (can not blow through it by mouth) when the EVAP vacuum cut valve bypass valve is de-energized.4. Verify the EVAP vacuum cut valve bypass valve opens (can blow through it by mouth) with the valve powered up and grounded.5. Check the EVAP vacuum cut valve to verify it allows flow only one way.
If it's "broken" then you have no breaks. More likely its leaking (internally or externally) and your breaks are soft, or need to be pumped. If it's just hard to break, check the power boost (a vacuum assist on most cars).
the heater controls are run on engine vacuum. When a engine is accelerating it has a drop in vacuum. There is a one way check valve that keep vacuum in the heater circuit that has gone bad. You could have it fixed or you can deal with it, its not that big of a deal
If it's the one in the engine bay you talking about, there is one that connects to the heater tap on joint to the heater hose.
Most all of the vacuum lines will start from the intake manifold in the rear..........
with your mouth
Start out by checking for a vacuum leak both inside and outside for the a/c and heater.........
You can find heater vacuum line diagrams for your Chevy van in most Chevrolet service manuals. The service manuals can be found at your local library.
Where is the vacuum pump for the heater located in a 1995 Ford F-250 Diesel? Ihave already changed the thermostat and the antifreeze, checked the heater switch and still no heat! Help
low water, bad thermostat, vacuum door not working, clogged up heater core, heater valve broken........
No vacuum change at the MAP sensor.
Perhaps a vacuum leak
When making any changes to a vehicle, a diagram can help point the person in the right direction. A vacuum line diagram for a 1988 Plymouth Horizon can be found in its maintenance manual.