Customer complaint: the AC didn’t work anymore. Also, the blower worked only on “high” speed only.
Diagnose: power transistor was defective.
Solution: replace the power transistor, change the cabin filters.
Work done: After thorough tests including AC system pressure, AC pressure switch, AC compressor, fuses and relays, we found out that the power transistor was defective. This might have happened because of lack of air circulation due to dirty cabin filters. After replacing the defective parts and the dirty filters, the system worked properly. Always replace the filters as part of the maintenance, it might prevent from damaging other more expensive components.

[Show as slideshow]

The glove box was removed to gain access to the cabin filters.

The old power transistor was removed from its place.

Another view of the old power transistor.

Here is the new power transistor ready to be installed.

The cabin filters were removed. You can see the evaporator core.

Here are the old dirty filters.

A comparison between the old dirty filter and a new clean one.