With that static pressure it should engage, provided the trinary switch is in position-3. The connector is a bit exposed, so does suffer corrosion.

It also depends if you have an early direct HEVAC feed, or the later relay version. Early HEVAC checks for compressor current, and will not engage if it's too low.
 
It’s got the relay late hevac system and a new trinary switch fitted will check that out again make sure all connected properly cheers
 
Make sure the relay actually switches. The switched 12V from the relay goes via the trinary switch to the compressor (White / Light-Green wire). The other side of compressor is grounded (Black wire).

The relay wiring depends on year. Later cars have the wiring in the loom. Early cars with later HEVAC will usually have the LR special loom !!
 
This is the later wiring diagram. Check for relevant voltages through the chain.

1692194729877.png
 
thanks pwood999 I’m not good at electrical but have spoken to my local Indy and he’s going av a look at it for me but as most good ones they busy but will get it sorted then sort out the respray
 

Similar threads