I want to repair the heating of a Mitsubishi Diamante - 1999

copy and paste

https://www.autozone.com/diy/repair-guides/mitsubishi-car-1999-05-removal-and-installation-repair-guide-p-0996b43f8037e77c

i had a similar problem, i noticed it only went off when i locked the car with the key. use the key to unlock the car, now only lock the car from buttons inside and not with the key.

Your 1999 Mitsubishi Diamante is a 3.5L MFI SOHC 6cyl engine.
MFI = multi-port fuel injection
SOHC = single overhead camshaft
This answer covers Mitsubishi Diamante1.8L, 2.4L, 3.0L (SOHC and DOHC), 3.5L, and 1997-2000 1.5L Engines.

2.4L engine shown, others similar.

Fig.1 - CKP position and its two mounting bolts


In Fig. 1, the two arrows point to the CKP (crankshaft position sensor) mounting bolts to remove. 2.4L engine shown.

Fig.2 - CKP reluctor removal

Remove the sensor and slide the reluctor wheel off of the crankshaft-2.4L engine shown.

1. Disconnect the negative battery cable.
2. Remove the timing belt.
3. Unplug the sensor connector.
4. Unfasten the two retaining bolts, then remove the CKP sensor from the vehicle.
5. Installation is the reverse of the removal procedure.

Reference: Autozone online repair guide: Mitsubishi Galant/Mirage/Diamante 1990-2000, at
www.autozone.com

Fig.3 - photo - new 99Diamante CKP, a Wells part #SU4313

check that one of the fans is not for the ac system and will not come on unless the ac is working. Check coolant level at the radiator cap

coolant low or heat control valve stuck shut..

check that the hot water can flow though the heater core and that the water control (tap) is working

1. check thermosat
2. both hoses near the heater core hot
3. watre circulating thats good
4. thermosat what it souds like

make sure the compressor is coming on if not probaly low on freo ,limit switch bad,when the compressor is on and the fan is removing condensed heat it will cool off

Yes there is a problem with your airbag system. Take it in asap

hi i have the same car same problem try changing plugs and wires car is over heating then starts again when it cools off