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No A/C--ECU?

gradon

NAXJA Forum User
Location
DC
Background:
A month ago, my A/C was working(not quite as cold as last year) and so my brother's friend used the leftover third of 134a to fill mine. I blew my 96 ecu a month ago(melted and shorted o2 wires) and temporarily replaced it with a 98 auto ecu. Two things not working since then, well three actually--tach(looking for a signal from the tcu?) the a/c doesn't engage, the aux fan doesn't turn on. I've since replaced the ecu with one from a 97 manual--have tach, but still no a/c. I checked fuses and swapped relays(from starter & fuel pump) and still no go. Now when you plug in the aux fan relay, it'll spin temporarily, so the fuse and relays aren't bad. On Saturday I disco'd the coolant temp sensor, which in turn puts the ecu in safe mode, so now the fan is on all the time(good for the cooling, but maybe not good if ecu thinks it's still cold and running a richer fuel map--I used the scanner today and the temp read -40*C, and of course the CEL for high CoolantTS voltage. Anyhow, the a/c compressor doesn't engage--do you think it's due to the wrong year ecu or should I keep on searching for the culprit?
 
I would say it's your ECU, those things are pretty picky, one glaring difference I've noticed between a 97 and a 98 is if you leave the trip odometer selected to trip when you turn off a 97 it defaults to the gross milage where the 98 will return to the trip meter. Now while a 97 may work on 97, 98 and *maybe* 99 I don't think it will work in a 96. They are also tranny specific, if you have a stick you need an ecu with the manual option, if auto you need the auto one.
 
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