93 FD3 The A/C will only works in level 4
 

Hello Guys,
I need advice, My A/C all of the sudden only works in the max level which is I beleive level 4. Some people say its probably the aftermarket radio interfering with the rear a/c cable but i think this makes no sense. Can anyone please shed some light. Thanks in advance for any support !!!

I would check and test the blower motor resistor. I have seen many different makes and models of cars with the same symptom and usually the resistor it's the culprit.

I will tell my mechanic to try this. Thanks

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