Heat on Cause Break Down - Corolla 2002

If you know the area of the car that was damaged, start there and look for any wiring cuts or possible shorts. After a crash, sometimes problems arise after repairs are made to the sheet metal but other, not so obvious problems exist only to be trouble later. My best guess is that you have a short or ground between the fan and or resistor wiring and the primary ignition system or fuel supply system such as the fuel pump. Does the engine stop suddenly, or sputter and run poorly before it dies? If you have the fan on only (try different fan speeds) and the heat control in cold, does it do the same thing? More information would be helpful for a diagnosis if you can.

In thirty something years of studying or performing car repairs, I thought I'd heard of just about every problem that can come up with a car, but this is new to me.

When you say the car "breaks down" do you mean that the engine idles roughly or do you mean that the engine stalls? If the engine stalls, does it re-start right away?

Do you know the extent of the damage from the accident? Where was the damage? Did the air bags deploy?

I'm wondering if the control cables for the heater control valve or fan speed are interfering with a wire for the computer. I would check ground points in the area where the body damage was repaired. Poor grounds are a common side-effect of body repairs.

I had something similar happen with a Ford Taurus. The AC compressor's bearing seized so badly that when I'd turn on the AC or defroster at idle, it would literally shut down the engine. If the car was moving, it would make a really interesting noise as the belt skidded over that pulley. :-)

I've seen that before.

The OP's heater and heater fan are not belt-driven.

Thanks for your input Ray.

I am unable to provide details for how exactly the accident was happened before. The garage told me that the radiator was replaced and some body work has been done to the front and the rear left door. The little lamps of the heat and the fan were never be on. In a year, I saw they were on only a couple of times. Is it the sign of something wrong with the electric circuits?

When the engine is idle while the heat and/or fan is on, the engine went roughly for a less then 5 seconds. Then the engine was shut off by itself. If I switch off the fan and/or heat, the car can be restarted without any problem at once.

Since a expert like you have never encoutered such a problem in 30 years, I will keep you posted once the cause is determined.

Casper

That sounds like quite a bit of body work! Assuming your car is left-hand drive like in North America, the fuse boxes for the car are both on the left side of the car - one under the driver's side of the dashboard and one in the engine compartment. This means most of the car's power comes from the side of the car that took the hit. There is the possibility that wiring and/or ground points were damaged. If a ground point has been painted, the connection to ground is sometimes insulated instead of grounded.

As far as the lamps for the heater control not working, the cause could be something as simple as burnt or damaged bulbs, poor connection somewhere, or damaged wiring. The say to diagnose is to check teh bulbs for continuity and check for voltage at the bulb sockets. If there is no voltaage at the bulb, check the fuses and associated wiring. If there is voltage at the sockets and the bulbs are good, check the grounds.

I'd suspect a poor ground connection, loose wiring connector, or damaged wiring. Start by checking in the area where body repairs were performed.