1986 Isuzu Impulse

Air Conditioning problem
1986 Isuzu Impulse 4 cyl Two Wheel Drive Manual 11400 miles

when I push the A/C button in there is no response from the A/C.
Also when I slide the fan lever, no fan kicks in.
I know it is an electrical supply issue so the fuse I checked and ichanged with new.
I am now going to change the relay but I have a feeling it is not the relay.
Where else can I troubleshoot this problem.
The light on the push button does not come on at all it has to be power supply problem but from where is is cut off?
April 28, 2010.

Hello and thanks for donating

follow the steps below to troubleshoot your vehicle's A/C power supply circuit..

Apr 30, 2010.