FordHater

Hi all,
I just bought a '97 c5 auto and am having troubly trying to sort out the codes.

I have "No Comm." for my HVAC system and no power to fuse 18 under the dash, when I hardwire the HVAC system it works perfect but obviously still "No Comm." I did some research and found that the orange wire off of the ignition should be giving Fuse 18 the power? When I test it, I have no power to the orange wire directly at the ignition when the key is on Acc. mode.





Should I have power at the Orange Wire when the ignition is turned to Acc?

Can anybody think of any possible causes for HVAC No COMM???

dadaroo

Not at home with the FSM but if the unit is not powered then it will "not be able communicate" It looks like when you power it you still get no communication so you seem to have two things going on.

I can tell you later but I would not think the HVAC unit would be powered in ACC except for bulb lighting.

FordHater

Thanks for the reply, even when the ignition is in the "On" position I still have no power at the Orange wire.

Correct me if I'm wrong, but when I hardwire the HVAC system and it works shouldn't it be able to communicate? Or is that done before the fuse panel?



Electrical stuff is not my strong point, so any help is much appreciated!!

dadaroo

If you have the automatic HVAC type then power if from fuse 27 Orange wire and also fuse 18 Brown wire. These are the wire colors from the fuse to the HVAC unit.

Fuse 18 is fed from the engine fuse box by an Orange wire.

FordHater

No luck trying to trace those wires, they appear to be fine. I am just going to hardwire it for now and take a look at it over the winter when the car is off the road.

Thanks very much for your help and input, much appreciated!



Cheers

dadaroo

Be glad to help you later. Just looking at wires does not tell you much.

Biotex

My electrical diagram shows fuse 18 is hot only in 'run'.
Wonder if the contacts are bad in your ignition switch???