I own a 2002 ford Focus ZX3. after replacing burnt out blower motor. I noticed that fan only works on high. A/C won't turn on. Switch lights up in fan mode 1,2,Or 3 and goes out when fan comes on on 4. A/C works in defrost mode and cycles fine. am I looking at a relay problem or a switch problem. Any help would be greatly appreciated. 2.0 zetech DOHC.