Heater problems?

Good morning.

Can you hear the blend door move when you go from heat to cool and back? It sounds like you have a clogged heater core this guide will tell us for sure

https://www.2carpros.com/articles/car-heater-not-working

You can flush it on your own. Remove the hoses to the core and use a garden hose to flush back and forth until debris is gone.

Roy

It may have been air in the system yes, rh heater core or it may have also been the blend door actuator.

Roy

Make sure the engine is running at a normal operating temp. With it warm, the engine running and the fan on high, feel both heater core hoses. IF both are hot, check the blend air door for operation. If only one is hot, flush the heater core.

As far as fan speed, replace the blower motor resister.

Check coolant level. Also, make sure the heater hoses are not pinched.

Suspect blower motor possible something got into cage. Remove motor check it out

Front and rear are seperate systems. Blower under dash pass. Side

"C" and "H" are cold and hot on the coolant temperature gauge. Low coolant level in the radiator will cause the flow to stop. That means no coolant coming from the radiator to cool the engine, so it gets too hot, and no hot coolant flowing through the heater core in the dash board, so it blows cold air.

There could be a cooling system leak. If this happened over a long period of time, it should have been addressed as a part of every oil change. Adding oil won't help an overheating condition.

The "flag" you're referring to could be a thermometer. Most Chrysler products have a "Check Gauges" light that comes on, along with a chime, when a gauge is indicating a problem.

Caradiodoc

Sounds like you have a rear heater. That would explain why the rear heat is good.

First, check to see if there is a calibration procedure for the computer. 1996 and 97 minivans needed this done anytime the battery was disconnected or went dead. It could be extremely frustrating to pass the tests, but I think by '99 it was no longer necessary to do this.

If you take it to the dealership, they will most likely try a different computer first. If you're lucky, that will solve the problem. Total repair will likely be around $300.00 to $500.00. Dual zone computers cost a lot more than the standard ones.

If there's no calibration procedure, and a new computer doesn't help, expect to find a broken temperature door inside the heater box, or a defective actuator. Both require removing the steering column and dashboard. The broken door repair also involves discharging the air conditioning system, and removing the heater box to disassemble it. Typical repair is commonly between $800.00 and $1200.00. That's a high price to pay for one person to be 2 degrees warmer than the other person, but people buy cars based on all these frills. It's also the reason I'm still driving a 1988 Grand Caravan. The front and rear heaters work just fine and there's not a single computer involved. So many people have been stung so many times by these repair bills, (be thankful you don't have a GM product), and the manufacturers can't figure out why no one wants to buy their cars!

Caradiodoc

The mechanic that replaced "motor that controls" may have left a vacuum hose off, follow the diagnostic procedure, to find out which hoes it is.

VACUUM CONTROL SYSTEM DIAGNOSIS
VACUUM CONTROL ONE-WAY CHECK VALVE
NOTE:Some models use brake booster check valve for vacuum source. These models do not use another in-line vacuum check valve.

In engine compartment, locate Black vacuum hose that runs from brake booster check valve or intake manifold, through firewall near heater hoses or expansion valve. This supply vacuum hose goes to A/C-heater control panel vacuum switch.
Within Black vacuum hose, disconnect and remove check valve near intake manifold or brake booster. Connect vacuum gauge to an external vacuum pump. Start vacuum pump. Plug end of hose probe on vacuum gauge. Adjust bleed valve on vacuum gauge to obtain an exact vacuum reading of 8 in. Hg.
Unplug and plug end of hose probe on vacuum gauge several times to ensure exact vacuum reading. Connect vacuum gauge hose probe to control panel side of check valve. Vacuum gauge reading should be 8 in. Hg. Replace check valve if vacuum leak exists.
Connect vacuum gauge hose probe to engine side of check valve. Vacuum should flow through check valve. Replace check valve if operation is not as described.
VACUUM CONTROLS
This test checks for proper function of control panel vacuum circuits. Perform steps 1) through 4) under VACUUM CONTROL ONE-WAY CHECK VALVE.
Connect vacuum gauge hose probe to Black vacuum hose end that leads to A/C-heater control panel switch. Position vacuum gauge so gauge reading can be observed from inside vehicle.
Operate A/C-heater controls (sliding lever or push buttons) in all mode positions (floor, defrost, panel, etc.). Pause after each selection to allow vacuum actuators or motors to energize and stabilize. Record vacuum gauge reading at each selection.
After each selection, vacuum reading should be 7.5-8 in. Hg. Maximum vacuum reading drop is.75 in. Hg. If proper vacuum reading cannot be obtained, vacuum leak exists in selected circuit.
To check for vacuum leak(s), disconnect 7-way A/C-heater control panel vacuum harness connector. See Fig. 1. If necessary, remove control panel from instrument panel to access A/C-heater control panel vacuum harness connector, or remove lower instrument panel assembly.
Connect vacuum source probe to each port of connector. See Fig. 1. Record each vacuum gauge reading. Vacuum reading should be 8 in. Hg at each port.
NOTE:Brown (bi-level) vacuum circuit contains a restriction in line. It takes longer to obtain correct vacuum reading on this line.

If correct vacuum readings are obtained, replace faulty A/C-heater control panel vacuum switch assembly. If proper vacuum readings are not obtained, check appropriate vacuum circuit.
Start vacuum check by plugging vacuum hose at vacuum actuator in suspect circuit. Recheck vacuum circuit by connecting vacuum source probe to proper port.
If proper vacuum reading is now obtained, replace vacuum actuator. If proper reading is not obtained, check vacuum hoses and connections for leak. Repair or replace as required.