P38A Air Con Woes,nanacom

Marty,

I used to think the same. I used to think that if the radio was working & not the hevac, it wasn't a becm fault as both the havac & radio are feed by the same feed. This was my mistake.
The Hevac can have power, but restricted performance.
To find these faults requires the circuits to be scoped while hot, & then you need a very sharp eye to catch it. It's all in the testing.
Every day we get surprised. It seem's the more we work with these modules show's how little we know about them. We learn new stuff every single day.

Sorted.
Someone had replaced the hevac head unit with the wrong one. Once i put the correct hevac unit (for the year) it now works fine. Thanks to all

rover75lover said:

Sorted.
Someone had replaced the hevac head unit with the wrong one. Once i put the correct hevac unit (for the year) it now works fine. Thanks to all

Click to expand...

That would suggest the Hevac unit was faulty. All should switch in the same way. Looking more closely at what relay 7 BECM supplies that could not have been the problem or you would have lost all sorts of things.

Ive only just bought her so i dont know if the air con was working or not before i had it but as the condensor way burst/split ,i changed it,receiver/drier,o rings and the expansion valve when i checked the air con pump ,it to was woofed so i changed it for another one. Once id done all of that,had it regassed checked the trinary and pressure switches ,when i called the air con in,it recorded a fault on the air con pump after about a minute. The nanacom said that the air con had been requested and granted from the becm and talking to ric the pic i kinda ruled the becm out. It was only when i changed the hevac unit for a correct one for its age that i managed to get it working,working well to i might add. Thinking about it though if i have a r3 aircon fitted in the fusebox i assume i must have the later wired rangey as the hevac unit only supplies power to the r3 relay and the aircon pump is fed from another separate power circuit via a fuse.
Anyways thanks to all and my rangey now defrosts dries out super fast. Ta again