NC Fairlane Air cond causing trans problems - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

olcoolone · 02-28-2004, 19:52

I run a air cond business here in Adealide and one of my trade customers is having a problem with the transmission in a customers NC Fairlane, the transmission down shifts when the car is warm and only when the air conditioning is on.
He (the trade customer) asked us to service the air conditioning because there was a problem and this problem was causing a transmission problem, we carried out tests before we serviced the air conditioning system and told him the air conditioning was fine and a air conditioning service would not make any differance.
He instructed us to carry out the air conditioning service as he has had this problem before and it was always the air conditioning that caused this problem with the transmission and he also said he had read it in the factory Ford manual.
The problem we have is we have not heard of this problem before and told him it is proberly another fault and the air conditioning just hilights it.
He is sure the air conditioning is at fault and has something wrong with it and has no other information on it, but like us, a Ford dealer and other people i have spoken to we all have not heard of this before.

Thanks in advance Richard

Aussiblue · 02-28-2004, 20:36

The air con system is linked to the trans. On initial start up of the air con, fourth gear is inhibited below 70 km/hr. Also under high air con loads the with continuous compressor clutch engagement of over 5 minutes the trans controller automatically selects 3rd gear if speed drops below 60 km /hr or 70 km/hr (depend if 6 or V8 or 85LE or 91 LE or 95 LE trans).The trans controller reads the air con clutch signal either from the low pressure switch (85LE ) or EECIV module (91/95LE). So a poorly performing air con will effect trans behaviour.

MADNC_8 · 02-28-2004, 20:54

Quote:

Originally Posted by Aussiblue

The air con system is linked to the trans. On initial start up of the air con, fourth gear is inhibited below 70 km/hr. Also under high air con loads the with continuous compressor clutch engagement of over 5 minutes the trans controller automatically selects 3rd gear if speed drops below 60 km /hr or 70 km/hr (depend if 6 or V8 or 85LE or 91 LE or 95 LE trans).The trans controller reads the air con clutch signal either from the low pressure switch (85LE ) or EECIV module (91/95LE). So a poorly performing air con will effect trans behaviour.

aussie thats interesting to know

olcoolone · 02-28-2004, 22:23

The air conditioning system is cycling correctly at aprox 3 to 4 minute, is there any way of testing anything else

Aussiblue · 02-29-2004, 04:10

I assume you have tried the air con self test. On warm engine with ignition on and engine on hold down the floor and off buttons together on the Climate Control Panel then release them. The air con will go through a self test procedure and display codes. If OK it wil read "Off" if not it will flash codes "E1" to "E7" if a code flashes press "auto" on the air con panel to see the next code.

The Transmission also has a self diagnostic mode and can also display codes if you have a code reader which will also confirm if the fault is caused by the air con or not, A code 67 is a air con fault. I suggest you do this first to confirm you are not wasting you time. Other no air con faults can cause downshifting symptoms. It might just be a loose wire. There is also a overheat mode which locks up third an fourth gear.

If you can tell me if it is a 6 or V8 and what trans fault it has (check if it shifts manually up and down OK), I may be able to offer other suggestions.

Aussiblue · 02-29-2004, 04:21

The info her http://www.autoemf.com.au/ford_eec5.htm and here http://www.autoemf.com.au/ford.htm and here http://www.autoemf.com.au/ford_acc.htm may also help you.