Thanks Tony! I might take you up once I learn a bit more about the modules, etc.

 

Here's the lowdown on the ABS circuit changes.

The 97 has a constant power fuse #10 = 10A that runs to relay 37 which then provides igniton switched power to the EBTCM or ABS. This relay coil has constant power and the other end of the coil is grounded the BCM by a wire which goes to the BCM on connector C1 terminal B7.

The export 97 has an ignition switched fuse #5 that runs through an external relay to power the EBTCM or ABS. This external relay coil also gets power from fuse 5 and has the coil grounded by the BCM at connector C1 terminal B7. No idea where this relay would have been mounted.

The 2001 ABS has a ignition switched fuse #5 connected directly to the module.

If you could put fuse 5 to use then it could be used to just power the ABS directly with no relay. It may be possible to do some rewiring under the underhood panel. The Hot In On power that feeds fuse 5 also feeds fuse 15.

I also believe the theft deterrent relay is always energized if the ignition key is correct. So, you could go with moving the wire from connector C1 terminal is B7 and jumper it to the theft deterrent wire at connector C3 terminal B7.

Here are the other wiring differences between BCM's, 1997 listed first and 2001 second.

Connector C1 terminals
*A6 - not used - ALC HDLP Relay Control
A7 - not used - Ambient Light Sensor Input
A10 - not used - Ambient Light Sensor Ground
B7 - ABSTRNS Relay Control - not used
B11 - {Fuse Output - Ignition 3 - Type III Fuse} - Not used

Connector C2 terminals
D11 - not used - Headlamp OFF Input
*D16 - {AAS Modulator Feed - LT RR} - DRL RH Relay Control

Connector C3 terminals
A5 - not used - Park Lamp Relay Control
*A7 - {AAS Modulator Output - Hold - LT RR} - DRL LH Relay Control

The ones with the * beside them probably need further investigation. I'm not sure what they do offhand. The rest appear to be for the twilight sentinel feature which was moved to the BCM later.

C1, B11 appears to be an ignition switched power feed going to the '97 BCM powered by fuse 22 that is not there on the '01 BCM so that's not a big deal even though it's called an output. Fuse 22 also has something to do with powering the DRL circuit.

There were other signals added for a convertible but I didn't bother with them since you can't have a rag top.

Peter

 

OK, I found the others on the schematics;

C1, A6 goes to a relay which bypasses the headlight switch and forces the headlights on. Much like C3, A5 does for the parking lights. Should be no big deal if not connected especially if the twilight sentinel is left off.

C2, D16 and C3, A7 do the same relay controls as the 2001 have. I have no idea what AAS Modulator Output is supposed to mean. They are outputs which run the DRL relays just like the 2001.

So, that about covers it. I don't see any reason why you can't run the 2001 BCM.

Peter

 

Thanks Peter!

 

SUCCESS!

I got it all swapped over today and working with no codes.

The programming is dead nuts easy with a TechII -- you don't even need to know the RPO codes. That the dealership said this was too hard to do baffles me...

The one hang up is that the Theft circuit (the yellow/black wire on C3 B7) is only grounded when the key is in the start position. First, I tried the ignition key resistor return wire (C1 B2) but found it was always grounded -- key on, key off, key on the seat... That would have been a constant battery drain and the relay would be hot all the time.

I ended up poking around with my DMM in ground test mode and found that C2 C15 (Steering Column Lock Signal) was grounded from key on until a few seconds after the key was removed. Since my car was an auto, and thus had the column lock physically removed, this works great.

I haven't driven it farther than 10 feet yet, but I think this is a win.

Very special thanks to Tony for letting me borrow his TechII (and hang on to it for far longer than expected).

Oh, I also turned off both the TPMS and the annoying code for not having TPMS in the car! This is in a different place than programming the RPO codes -- its under the tire pressure diagnostic screen in the "body" section.

This may be more of a headache on a car with more options. The only electrical conflict I had was the ABS/TCM. I'm not sure what kind of gremlins might pop up if you have a ton of options.

 

Hey Erik,

Glad you got it all worked out. Now you need to post up some pictures.

 

Doh! Just put it all back together lol

 

I seem to be draining the battery with the key out. See: my SLC and bypass thread for one avenue I'm pursuing.

There are no obvious culprits -- no lights on, no bells, etc., just a slow drain. I've check the ABS circuit and it appears to be off every time. The DRLs are not powered (first thought maybe the AAS modular might be freaking out, but it appears to be normal.

 

Hook up a multimeter and start pulling fuses.

 

Haha -- yeah that's my fall back plan

I love electrical work so much, though, that I'd much rather have a plan A of things to look at

 

Hey Tony, I attached my DMM across the battery terminals for some simple testing.

But first, I slapped the charger on it -- it ran for less than 5 minutes and then reported the battery full (12.98v)

Here are some readings (in order tested) comparing the DIC and the DMM across the battery ( test , DIC volts, DMM volts)

Key out -- 12.4v
Key on (relay out) -- 11.2v -- 12.23v
Key on (relay in) -- 11.4v -- 12.08v
Key out -- 12.2v (and was climbing slowly).

About 20 minutes ago the DIC read 10.9v...

The first battery did die over a couple of days of inactivity, but after replacing the battery, it has not gone flat (then again I drove it yesterday, and ran it for less than 5 minutes this morning).

I'm starting to wonder if the 2001 BCM is simply misreporting the voltage (although it reads 14.1v at idle).

 

Hi Erik,

The PCM controls the re-charge (alternator) voltage.

Your voltage measurements are somewhat jumpy and not stable. I thought you wrote earlier that the battery you used as a replacement might have a dead cell or you thought the previous battery had a bad cell.

Either way, I would disconnect the battery cable (Positive) and trickle charge the battery overnight so that you get a good charge and re-do your test.

You might also want to take some measurement inside the passenger footwell, where the battery cable runs into, to power the passenger fuse box.

BTW, do you have the telescopic wheel option ?

 

I just checked the battery again (key off, ~25 minutes later ) and it was 12.37v.

No telescopic wheel option. Yep, you are right though -- I thought the old battery had a bad cell and replaced it with a brand new optima yellow top (same as the old).

I'll disconnect it and charge it at 2A (lowest setting my charger has).

 

Have you conducted a battery current draw test? That the correct way to see whats wrong. Insert your meter in between the negitive battery cable terminal an the Negative battery terminal.

The BCM Sleep current draw should be 20 milliamps.

BC