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Anonymous Posted on Nov 24, 2011

The heater in my 1991 wrangler doesnt give out warm air. No real heat

I have a 4.0 litre with no air conditioning. When I set it to heat, the fan blows air but not warm air so I get no real heat. Is this problem the thermostat?

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  • Posted on Jul 13, 2013
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Probably have a blockage in the heater core or heater hoses to the core

5 Related Answers

dennymulford

Dennis Mulford

  • 1055 Answers
  • Posted on Mar 04, 2009

SOURCE: heater doesnt get hot

is their a control valve in the heaater hose?
if so it could be stuck

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Anonymous

  • 1489 Answers
  • Posted on Apr 28, 2009

SOURCE: heater doesn't blow warm air. Not the thermostat

Sounds like either the valve which lets water into the heater core is not working properly or the vacuum operated door which directs blower motor air over the heater core is not opening, Could be a vacuum hose loose or it has a hole in it.

If you want to further discuss, let me know,

Anonymous

  • 396 Answers
  • Posted on Oct 16, 2009

SOURCE: Heater not blowing warm air. Thermostat has been

Check the water control valve behind the engine close to the firewall. This valve opens and closes to allow hot coolant to enter the heater core. It is usually connected to the heater controls with a cable. When you adjust the heater control for heat, a cable activated lever on the valve should move and allow coolant to move through the valve. The cable from the heater control can come loose from the lever, or the valve itself can become corroded and hard to move.

Anonymous

  • 49 Answers
  • Posted on Dec 15, 2010

SOURCE: MY 1991 JEEP WRANGLER CARS HEATER DOESNT WORK

If the blower works check for coolant in the cooling system. Test operation of thermostat. Check heater control valve for proper operation if equipped. Pressure test cooling system to ensure system holds pressure (this will help you identify a leak, if any. If car does not over heat and cooling system is in good working order, then the heater core is clogged.
If the blower does not work Check fuse, relay, wiring for short to ground, apply direct battery voltage to blower motor. If blower motor turns on and fuse/relay and wiring are ok replace the switch.

Anonymous

  • 836 Answers
  • Posted on Dec 29, 2010

SOURCE: 1997 jeep wrangler will not

sounds like either the antifreeze solution is to strong [ shouldn't be more then a 70% mixture ] or the heater core is plugged [ some "stop leak" products will cause this.

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Related Questions:

0helpful
1answer

My 2009 Jeep Wrangler fan wont run in normal operation,fan will run if I turn the Air on.

which fans, there are up to 4 fans
1 condenser.
2: radiator can have 1 or 2.
3: heater blower. fan.

what is normal operation.?????

my guess is this is and HVAC question.
but what works and what don't
are you heating car.
cooling car
or running front defrost that fails.

all 3 are normal.
tip

Tips for operating Air conditioning system on Toyota Hilux and someother...

To cool off your Toyota after it has been parked in the hot sun, drive with the windows open for a few minutes. This vents the hot air, allowing the air conditioning to cool the interior more quickly.

Make sure the air intake grilles in front of the windshield are not blocked (by leaves or snow, for example).

On humid, do not blow cold air on the windshield. The windshield could fog up because of the difference in air temperature on the inside and outside of the windshield.

Keep the area under the front seats clear to allow air to circulate throughout the vehicle.

On cold days, set the fan speed to high for a minute to help clear the intake ducts of snow or moisture. This can reduce the amount of fogging on the windows.

When driving on dusty roads, close all windows. If dust thrown up b the vehicle is still drawn into the vehicle after closing the windows, it is recommended that the in intake be set to FRESH and the fan speed to any setting except "OFF".

If following another vehicle on a dusty road, or driving in windy and dusty conditions, it is recommended that the air intake be temporarily set to RECIRCULATE, which will close off the outside passage and prevent outside air and dust from entering the vehicle interior.

HEATING

For best results, set controls to;
Fan speed ---- Any setting except "OFF"
Temperature----Towards WARM (red zone)
Air intake ---- FRESH (outside air)
Air flow ---- FLOOR
Air conditioning ---- OFF

For quick heating, select recirculated air for a few minutes. To keep the windows from fogging, select fresh after the vehicle has been warmed.

Press the "A/C" button on for dehumidified heating.

Choose floor/windshield air flow to heat the voltage interior while defrosting or defogging the windshield.

AIR CONDITIONING

For best results, set controls to;

Fan speed --- Any setting except 'OFF"
Temperature --- Towards COLD (blue zone)
Air intake --- (outside air)
Air flow --- PANEL
Air conditioning --- ON

For quick cooling, move the air intake selector to recirculate for a few minutes.

VENTILATION

For best results, set controls to;

Fan speed --- Any setting except 'OFF"
Temperature --- Towards COLD (blue zone)
Air intake --- (outside air)
Air flow --- PANEL
Air conditioning --- ON

DEFOGGING

The inside of the windshield

For best results, set controls to:

Fan speed --- Any setting except 'OFF"
Temperature --- Towards WARM (red zone) to heat; COLD (blue zone) to cool
Air intake --- FRESH (outside air)
Air flow --- WINDSHIELD
Air conditioning --- ON

The outside of the windshield

For best results, set controls to:

Fan speed --- Any setting except 'OFF"
Temperature --- Towards WARM (red zone)
Air intake --- FRESH (outside air)
Air flow --- WINDSHIELD
Air conditioning --- OFF

On humid days, do not blow cold air on the windshield. The windshield could fog up because of the difference in air temperature on the inside and outside of the windshield.

DEFROSTING

The outside of the windshield

For best results, set controls to:

Fan speed --- Any setting except 'OFF"
Temperature --- Towards WARM (red zone)
Air intake --- FRESH (outside air)
Air flow --- WINDSHIELD
Air conditioning --- OFF

To heat the vehicle interior while defrosting the windshield, choose floor/windshield air flow.
0helpful
1answer

MY 1991 JEEP WRANGLER CARS HEATER DOESNT WORK

If the blower works check for coolant in the cooling system. Test operation of thermostat. Check heater control valve for proper operation if equipped. Pressure test cooling system to ensure system holds pressure (this will help you identify a leak, if any. If car does not over heat and cooling system is in good working order, then the heater core is clogged.
If the blower does not work Check fuse, relay, wiring for short to ground, apply direct battery voltage to blower motor. If blower motor turns on and fuse/relay and wiring are ok replace the switch.
0helpful
1answer

1999 Jeep Wrangler - 4cyl - 5 speed. Where do I start if my heater is not getting hot. Really doesn't get warm. Just blows out cool air. Side note: This is my 3rd winter with this Jeep and it's never...

The temp reading on the dash is a very big clue... Likely the thermostat (at the end of the large top radiator hose inside the metal housing) is stuck open. When that happens, the coolant in the engine never reaches full temp. Not only can that result in a low heat condition but it can also give you poor fuel mileage as the computer always thinks the engine is cold and therefore it adds extra fuel to keep it running.
Replace with a 195 degree(f) thermostat, run the engine (with the heater on full heat) to nearly normal temp, turn it off and wait about three minutes, then re-start and continue filling. Once full, add whatever is necessary to the recovery bottle and close it up and check for leaks.
0helpful
1answer

I have an 04 jeep wrangler i had an accadent got the body fixed but now the heater only works when i give the jeep gas but the fan works fine

There are two possibilities here. If the system is air bound or the coolant level is low it can act like that. Check to make sure coolant is full...If it is, remove the cap and start the engine and let it run till it reaches operating temp, keeping the heater on high heat setting.
After it is fully warmed up, add more coolant if necessary.
The other item is the vacuum system. If there is a minor vacuum leak, there may not be enough vacuum to open the control doors for the heater. Since it was hit, I'd check all vacuum connections, lines and also the vacuum reservoir behind the front bumper inside the right fender (most common location) to make sure everything is intact. The leak would have to be small though or the system would not work at all so look carefully.
1helpful
1answer

Heater blows air-not warm-when on heat; warm air comes when set on MAX (AC). where is the vaccuum tube for heater?

look on the passenger side for a small hose that runs from the inake manifold or throdle body to the firewall above the heater.
0helpful
1answer

Why wont the heater blow hot air, the core doesnt look clogged?

Hi


Thanks for using FixYa. Try and check if the heater core is plugged. Find the 2 coolant lines going to the heater core. They are right next to each other with approx 3/4" hoses going to the engine. Now, warm up the engine with the heater on max (don’t turn on the fan). Next, feel if the hoses are warm (maybe HOT!) If they are not warm, then you most likely have a plugged core. A back flush will resolve the issue. If your hoses are warm, turn on the fan. One hose should go cold (or cooler than the other, actually should be about the same temp as the air from your air vents, if there is a plug). If both hoses are hot and stay hot, and you have no heat, then the problem is not with the heater core but with the blend doors.


There are electric motors that operate the "blend doors" inside the dash directing air flow from the heater core and A/C evaporator core to the cab of the vehicle. If you feel a drastic difference in one of the radiator hoses, then try replacing the thermostat and see what happens. If all the heater and radiator hoses are pretty much the same temperature I would suspect a control problem in the dash controls or in the blend door operation. You’ll need to remove the dash to check these.


Please do accept the solution if the issue is resolved or else revert for further assistance.


Thanks

Rylee

0helpful
2answers

When weather gets below -15 C, truck has a hard time to start almost like no gas. After it turns over several time it will finaly start.

Make sure you use synthetic oil with a low viscosity,and if you do not have a garage, get a block heater to prevent these dry starts that are potentially damaging.
11helpful
3answers

1991 cadillac deville NO HEAT

I had the same problem in my 1991 caddy, and turned out to be the blend door. It is located in back of the glove compartment. There are two kinds, the automatic blend doors and the manuel ones. Since the temperature is automatic and programmed to stay where it is set, it would be an "automatic blend door". Not a hard fix...
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