need big help with a 98 jetta

[liviu26]

A week ago my engine light turned on. I went to Autozone, they checked the message and it seems that my vehicle speed sensor is malfunctioning.
Though I don't think this is the problem because the check engine light turns on only when I turn on the air conditioning and afte I turn off the air and drive fo 20 miles the check engine light turns off. Also when i turn on the air my turn signal bulb on the right side blows, si I think it's something wrong with the electrical system. I already checked the fuses and those are ok.
What do you think guys?
I need help.
Thanks