WACKY 3 channel/4 channel confusion, help needed
01-03-2011, 02:34 PM
#1
11 Second Club
Thread Starter
iTrader: (43)
WACKY 3 channel/4 channel confusion, help needed Working on my buddies 99 Z28. The "original" job was for me to build him a 4 channel 10 bolt rear and swap it for his 3 channel presently in the car...(he assumed that since the car has the ASR button, it had simply gotten the wrong rear installed sometime before he owned it)
He has 3 channel rear in the car. Wiring harness has just the one wire going to the differential, plugging into the factory 3 channel ABS sensor. There's only the two brakelines going to each caliper, and where the wiring connector comes through the driver's side rear floorboard, it looks like it's all original and un-touched.
Here lies the problem...
Car has an ASR button on the dashboard, above the radio, where they usually are.
Car has all the brake related warning lights illuminated.
ASR, ABS INOP, BRAKE
Owner of car checked codes and code said faulty left rear abs sensor...
Now I KNOW that only 4 channel cars (ASR/TCS) have 4 wheel sensors.
I also know that only 4 channel cars should have the ASR button.
Like I said, code says LR sensor is bad, but the car definitely has a 3 channel rear in it right now, and it looks like it's been there forever...
On my old 2000 SS, I am 99% sure that I had more wiring and brakelines than this car has, so what the heck is going on here?
Does anyone have a picture of the 4 channel wiring/plumbing under the rear of the car? I strongly feel that this car's wiring/plumbing looks different than my old 2000 Camaro did.
He has 3 channel rear in the car. Wiring harness has just the one wire going to the differential, plugging into the factory 3 channel ABS sensor. There's only the two brakelines going to each caliper, and where the wiring connector comes through the driver's side rear floorboard, it looks like it's all original and un-touched.
Here lies the problem...
Car has an ASR button on the dashboard, above the radio, where they usually are.
Car has all the brake related warning lights illuminated.
ASR, ABS INOP, BRAKE
Owner of car checked codes and code said faulty left rear abs sensor...
Now I KNOW that only 4 channel cars (ASR/TCS) have 4 wheel sensors.
I also know that only 4 channel cars should have the ASR button.
Like I said, code says LR sensor is bad, but the car definitely has a 3 channel rear in it right now, and it looks like it's been there forever...
On my old 2000 SS, I am 99% sure that I had more wiring and brakelines than this car has, so what the heck is going on here?
Does anyone have a picture of the 4 channel wiring/plumbing under the rear of the car? I strongly feel that this car's wiring/plumbing looks different than my old 2000 Camaro did.
01-05-2011, 10:11 AM
#2
First step is to find out what the car was as it left the factory,3channel ABS or 4channel ABS + ASR.
4channel option code is NW9.
this thread should have been posted in the gears and axles forum,even though your concern is brakes,the root of the problem is 3channel or 4channel vehicle. There are many threads of trying to use an incompatible rearend in a car(3channel rearend into a 4channel car and 4channel rearend into a 3channel car) and what needs to be done to get the wrong rearend to work as far as ABS/ASR/dash lights.
sounds like at some time a 3channel rear was put in the 4channel car and somebody just started plugging things in and MAYBE removing some wiring.
IF all the original wiring and plugs still exist and are in/attached to the system,all that is needed to convert a 3channel rearend for use in a 4channel car is to use 4channel axles w/reluctor rings and 4channel backing plates w/sensors.
4channel option code is NW9.
this thread should have been posted in the gears and axles forum,even though your concern is brakes,the root of the problem is 3channel or 4channel vehicle. There are many threads of trying to use an incompatible rearend in a car(3channel rearend into a 4channel car and 4channel rearend into a 3channel car) and what needs to be done to get the wrong rearend to work as far as ABS/ASR/dash lights.
sounds like at some time a 3channel rear was put in the 4channel car and somebody just started plugging things in and MAYBE removing some wiring.
IF all the original wiring and plugs still exist and are in/attached to the system,all that is needed to convert a 3channel rearend for use in a 4channel car is to use 4channel axles w/reluctor rings and 4channel backing plates w/sensors.
01-05-2011, 04:12 PM
#3
11 Second Club
Thread Starter
iTrader: (43)
First step is to find out what the car was as it left the factory,3channel ABS or 4channel ABS + ASR.
4channel option code is NW9.
this thread should have been posted in the gears and axles forum,even though your concern is brakes,the root of the problem is 3channel or 4channel vehicle. There are many threads of trying to use an incompatible rearend in a car(3channel rearend into a 4channel car and 4channel rearend into a 3channel car) and what needs to be done to get the wrong rearend to work as far as ABS/ASR/dash lights.
sounds like at some time a 3channel rear was put in the 4channel car and somebody just started plugging things in and MAYBE removing some wiring.
IF all the original wiring and plugs still exist and are in/attached to the system,all that is needed to convert a 3channel rearend for use in a 4channel car is to use 4channel axles w/reluctor rings and 4channel backing plates w/sensors.
4channel option code is NW9.
this thread should have been posted in the gears and axles forum,even though your concern is brakes,the root of the problem is 3channel or 4channel vehicle. There are many threads of trying to use an incompatible rearend in a car(3channel rearend into a 4channel car and 4channel rearend into a 3channel car) and what needs to be done to get the wrong rearend to work as far as ABS/ASR/dash lights.
sounds like at some time a 3channel rear was put in the 4channel car and somebody just started plugging things in and MAYBE removing some wiring.
IF all the original wiring and plugs still exist and are in/attached to the system,all that is needed to convert a 3channel rearend for use in a 4channel car is to use 4channel axles w/reluctor rings and 4channel backing plates w/sensors.
and I agree 100% about the rear swap in the past...
Anyway, it is NW9 car, according to door sticker.
I have already removed the 3 channel rear, and in it's place is a complete 4 channel rear, except for backing plates, which I have yet to locate. I swapped a 3 channel housing into my old 2000 SS Camaro and know that you also have to clearance the axle flanges, but this car's owner didn't want to modify the existing (3 ch) rear, and chose to replace it with complete rebuilt 4 channel rear.
I took pics of the brake wiring connector under driver's side rear passenger floorboard, and of "motor" that goes on passenger side strut tower near battery. Hopefully, someone can tell me WTF is going on with this car so I can get it the heck out of my driveway...
BTW, open spot on wiring harness is where I unplugged harness that went to three channel sensor on old rear.
Last edited by rel3rd; 02-06-2020 at 08:42 AM.
01-05-2011, 04:49 PM
#4
backing plates are typically at a premium as they're swapped over to aftermarket rearends.
Do a 'search' for 'backing plates' in the classified forum here on this site and on
ls1.com
camaroZ28.com
fbodyonline.com
can't help you in the wiring/system area as that's an area beyond me.
find a 4channel car to research what's needed/compare to.
Do a 'search' for 'backing plates' in the classified forum here on this site and on
ls1.com
camaroZ28.com
fbodyonline.com
can't help you in the wiring/system area as that's an area beyond me.
find a 4channel car to research what's needed/compare to.
01-05-2011, 05:02 PM
#5
11 Second Club
Thread Starter
iTrader: (43)
I haven't looked that closely at the 3 channel backing plates, but if they are able to be slotted somehow, I may do that and go ahead and installed the axles and modified backing plates until a 4 channel set can be found. That way I can swap the backing plates without pulling the axles out...no idea, at this point, if that's possible, but if it is, that's going to happen soon.
Someone on another site suggested getting a 4 channel harness and splicing the sensor leads together and plugging into the 3 channel sensor, but since I already swapped rears, that option is gone too, lol...frickin headache this car is...
p.s. Thanks for the links, I'll do some looking later tonight...
