1999 Grand Prix 3.8 V6. Replaced Blend air door actuator and Thermostat 195F.
Question: Had heat only coming from drivers side, replaced blend air actuator on pass side and had heat on both sides. Worked for about 1 month then yesterday my heat just stopped working. Only cold air blows out. Auto A/C , heat control seems to be working fine.
Water Temp gauge is not holding temp., it fluctuates, as soon as engine temp is reached it drops to below 160 then starts to climb back up.
Answer: It is very possible that the short circuit caused damage inside the rear fuse block. A short circuit that was enough to blow 125 amp, could surely melt any part of the inside of the fuse block. May have also melted some feed wires under the block.
I would remove it and look at the wires to see if one or more are shorted together. If not, it may internal to the block.
Serpentine Belt Removal
Heat Only On Drivers Side Vents
99 Pontiac Grand Prix GT.
Engine Size : 3.8
Why does my heat only blow out on my 2 passenger side vents and cold air out the other 3 vents?
Answer: A problem with the drivers side temperature door actuator motor is most common. Each side has a motor to control the vent temperature. It is located under the drivers side of the dash. You can try to tap on it, or unplug it to see if it will reset, but it will usually start acting up again, so replacement would be needed.