TomServo Posted July 8 Share Posted July 8 First, I am more than certain I have an SBEC and not an SMEC. The SBEC for a 1990 LeBaron 3.0 V6 appears to be virtually the same, but nothing official says they are interchangeable. I have studied the wiring schematics and pin configuration for both SBECs, and am convinced they are interchangeable. One picture is the SBEC 60-pin configuration for my 1991 TC 3.0 V6 The other is the configuration for the 1990 LeBaron Pins 4,8, and 9 are labeled slightly different, but when looking at the full schematics the wires are the same color and go to the same things. I would love to get a backup SBEC as soon as I can, and the LeBaron one is scarce but available for less than $300 Am I being too overconfident in my conclusion that this would work as I expect it to? 1 1 Link to comment Share on other sites More sharing options...
Hemi Dude Posted July 8 Share Posted July 8 Get it, they are similar and you should find no difference in performance. There are likely minor variations, between CA and Federal, but that should not concern you. 1 Link to comment Share on other sites More sharing options...
Hemi Dude Posted July 8 Share Posted July 8 Thanks for the fabulous schematic, everyone should save a copy. Link to comment Share on other sites More sharing options...
TomServo Posted July 8 Author Share Posted July 8 (edited) This is great news, thank you for helping confirm this for me, and hopefully someone else can use this information for themselves. Edited July 8 by TomServo (see edit history) 1 Link to comment Share on other sites More sharing options...
TomServo Posted July 13 Author Share Posted July 13 @Hemi DudeThe reason I was seeking a replacement in the first place is I'm getting code 41, Alternator Field Control (on a 3.0 V6). The alternator in the car looks brand new...but I suppose it could still be 'bad' or weak? The gauge doesn't show a problem while I'm driving, and it has never failed to turn over and start. My '86 LeBaron had an external voltage regulator, little black box on the firewall area. This seems to be part of the SBEC on my 1991 TC, and not an external part that can be replaced? If the alternator checks out as fine...I'd have to repair or replace the SBEC to fix it? Of course, I could be down the wrong thread trying to find a solution. Link to comment Share on other sites More sharing options...
Hemi Dude Posted July 13 Share Posted July 13 Have you tested the wiring harness especially below the battery leading to the SBEC? There is of course a possibility that the SBEC has failed, but it is very rare on our cars. Link to comment Share on other sites More sharing options...
TomServo Posted July 13 Author Share Posted July 13 Thanks, I'm going to (carefully!) check that out this weekend. Seems to run and charge fine despite the code, and I suppose there's no way of knowing how/when/if it would cause further malfunction. Link to comment Share on other sites More sharing options...
TomServo Posted July 13 Author Share Posted July 13 (edited) Something I forgot to add, the shop replaced a connector to the battery that was all crusty and nasty. That could have made it store the code...but I figured it would clear the code once it started getting normal readings. Maybe I should just disconnect the battery for a little while and see if the code comes right back. I fixed the cruise control stuff so that code (34) should get cleared as well. Only thing I found was this 2 wire connector. I took forever to scour the wiring diagrams, which I'm terrible at reading, and this was the closest thing I could find and it seems like there's a chance it is related. I believe it to be the 'ignition off draw' connector. This goes to the Automatic Shutdown Relay, which in some forums it is said that controls the alternator field somehow? The red/white wire wasn't quite all the way in, but still seemed connected for the most part. I could see a bit of bare wire and looked like a bit of corrosion on it. Am I on to something here!? Edited July 13 by TomServo (see edit history) Link to comment Share on other sites More sharing options...
Hemi Dude Posted July 13 Share Posted July 13 3 hours ago, TomServo said: Something I forgot to add, the shop replaced a connector to the battery that was all crusty and nasty. That could have made it store the code...but I figured it would clear the code once it started getting normal readings. Maybe I should just disconnect the battery for a little while and see if the code comes right back. I fixed the cruise control stuff so that code (34) should get cleared as well. Only thing I found was this 2 wire connector. I took forever to scour the wiring diagrams, which I'm terrible at reading, and this was the closest thing I could find and it seems like there's a chance it is related. I believe it to be the 'ignition off draw' connector. This goes to the Automatic Shutdown Relay, which in some forums it is said that controls the alternator field somehow? The red/white wire wasn't quite all the way in, but still seemed connected for the most part. I could see a bit of bare wire and looked like a bit of corrosion on it. Am I on to something here!? See the RED arrow? Pointing to the burnt out orange fusible link I told you about in the beginning. Replace the fusible link and test for the reason it burned out! BEFORE applying power to the repaired circuit. 1 Link to comment Share on other sites More sharing options...
TomServo Posted July 13 Author Share Posted July 13 Thank you for the knowledge you have bestowed. I'm short on tools for wiring problems, gonna grab some next week and hopefully report back on findings. You can tell it is burnt out just by looking at the picture? Thanks again you know just about everything there is on these cars. Link to comment Share on other sites More sharing options...
Hemi Dude Posted July 13 Share Posted July 13 29 minutes ago, TomServo said: Thank you for the knowledge you have bestowed. I'm short on tools for wiring problems, gonna grab some next week and hopefully report back on findings. You can tell it is burnt out just by looking at the picture? Thanks again you know just about everything there is on these cars. Experience. I started my Chrysler mechanic career in 1959. Have worked on them ever since, a little less these days but I’m not blind yet. Look closely and you can see the insulation burnt away and the broken conductor. It is just knowing how and where to look. Link to comment Share on other sites More sharing options...
TomServo Posted July 13 Author Share Posted July 13 If you have the time, could you elaborate on the context of how this orange fusible link wire could cause the code 41? Just limited voltage to the SBEC due to being burnt a bit, and the low voltage is tripping the code? Before I actually do the thing, I'd like to understand as much as possible so I don't do anything daft. That's why I'm studying the wiring diagram carefully, and I believe I have found the relevant part which I have highlighted. The C13 20OR orange wire shows a fusible link, and it can be traced to the SBEC. There are other 20OR wires that show having fusible links but those do not trace to the SBEC. That is all my detective work has come up with so far. Link to comment Share on other sites More sharing options...
Hemi Dude Posted July 14 Share Posted July 14 6 hours ago, TomServo said: If you have the time, could you elaborate on the context of how this orange fusible link wire could cause the code 41? Just limited voltage to the SBEC due to being burnt a bit, and the low voltage is tripping the code? Before I actually do the thing, I'd like to understand as much as possible so I don't do anything daft. That's why I'm studying the wiring diagram carefully, and I believe I have found the relevant part which I have highlighted. The C13 20OR orange wire shows a fusible link, and it can be traced to the SBEC. There are other 20OR wires that show having fusible links but those do not trace to the SBEC. That is all my detective work has come up with so far. "If you have the time, could you elaborate on the context of how this orange fusible link wire could cause the code 41? Just limited voltage to the SBEC due to being burnt a bit, and the low voltage is tripping the code?" OK, first of all, gently clean the wiring in the area of the fusible links and blow them dry with compressed air if needed. In looking closely, with all the dirt on the links it is possible that it is a different colored link, therefore a different circuit. It is hard to follow in that bundle. You need to verify this first of all. Then we can trace what components are supplied power and determine if this also affects the alternator field circuit. Take it one step at a time, let me know the color of the affected fusible link. Link to comment Share on other sites More sharing options...
TomServo Posted July 14 Author Share Posted July 14 (edited) Someone tightened the bejesus out of the zip tie, but I couldn't find any one particular fusible link that was convincingly bad. Let me know what you think. I just noticed the battery is from 2018...could just be the battery this whole time I might has well get it tested and I think they can get an idea of the charging system at the same time. Unhooked the battery for 5 minutes, hooked it back up, when for a 30 minute drive and the check engine light has not come on. We'll see how long that lasts. Edited July 14 by TomServo (see edit history) Link to comment Share on other sites More sharing options...
Hemi Dude Posted July 15 Share Posted July 15 Now that they are clean, all the fusible links look good, even the gray one that looked burnt out to me. I hope you took the time to clean the engine and the entire engine compartment. Link to comment Share on other sites More sharing options...
TomServo Posted July 18 Author Share Posted July 18 Strange place to get one from, but gonna try my luck on this Cardone SBEC that is on....Amazon of all places: https://www.amazon.com/Cardone-79-6343-Remanufactured-Chrysler-Computer/dp/B000C49OFG Link to comment Share on other sites More sharing options...
Hemi Dude Posted July 18 Share Posted July 18 (edited) 21 minutes ago, TomServo said: Strange place to get one from, but gonna try my luck on this Cardone SBEC that is on....Amazon of all places: https://www.amazon.com/Cardone-79-6343-Remanufactured-Chrysler-Computer/dp/B000C49OFG Edited July 18 by Hemi Dude (see edit history) Link to comment Share on other sites More sharing options...
Hemi Dude Posted July 18 Share Posted July 18 This module listed on Rock Auto does appear to be compatible with the TC 3.0 engine 1 Link to comment Share on other sites More sharing options...
Hemi Dude Posted July 18 Share Posted July 18 If you purchase this module, when you receive it, be sure to install and test it before sending your ‘CORE’ back. If it doesn't fix the problem, try to get permission to return it for credit or your payment canceled. You have not convinced me that you need to replace your current module. Link to comment Share on other sites More sharing options...
TomServo Posted July 18 Author Share Posted July 18 I'm not sending my current one back for the core charge because I'm not convinced either. I'll install it to make sure it works and then just put the original one back in until it bites the dust, then I'll have the backup. Drove the car all over Texas today, check engine light on the hour drive there but not on the way back. Such a fun ride, still can't believe I have one of these unique automobiles. I found a burnt spot in the trunk where the wiring harness goes to the brake lights, which is likely why the fuse was blown when I got the car. Calls for an investigation! Link to comment Share on other sites More sharing options...
Hemi Dude Posted July 18 Share Posted July 18 Tom, you might bite the dust before the original one does. Lol 😂😉. I rarely seen any SMEC or SBEC to fail. But you will have the other one in case ‘someone else’ might need one. Link to comment Share on other sites More sharing options...
TomServo Posted August 8 Author Share Posted August 8 (edited) Hello again! I replaced the SBEC! It was indeed a compatible one, took it for a drive and everything was working as I expected and it ran fine. For the future people that may land here wanting to know the answer: yes it is compatible grab one from a 1990 LeBaron 3.0 V6 if you can't find one for your 1991 TC 3.0 V6. I'm getting a code 35 (cooling fan circuit open/shorted), and code 62 (something about not being able to write mileage to the EEPROM). From what I can tell...these two codes might be 'normal' when installing a reman SBEC? I'm NOT getting fault code 41 anymore (so far)! Fun note: the SBEC that was in my car was apparently a re-manufactured one! I'm keeping it for now, it can likely be repaired by the right person. Edited August 8 by TomServo (see edit history) Link to comment Share on other sites More sharing options...
Hemi Dude Posted August 8 Share Posted August 8 Try clearing the codes, they are likely left over from the previous vehicle. 2 Link to comment Share on other sites More sharing options...
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