2nd Gen Ram Tech1994-2001 Rams: This section is for TECHNICAL discussions only, that involve the 1994 through 2001 Rams. For any non-tech discussions, please direct your attention to the "General discussion/NON-tech" sub sections.
99 3500 4x4 Cummins with 4WAL (4-wheel / all wheel ABS). ABS light and Brake light are on. ABS scanner shows code 53 (rear isolation solenoid short circuit). Can someone tell me which pins on which connector I probe with my ohmmeter to test the rear isolation solenoid? Also, what the ohm range should be.
I've found some info through searches, but all of them refer to trucks equippend with only RWAL (rear wheel ABS). On those trucks, the isolation solenoid is mounted on a block located below the proportioner. With 4WAL, I assume it's located inside the ABS unit, next to the master cylinder. I have AllData, but the wiring diagrams don't show ABS in detail.
I've replaced the rear speed sensor (on the rear diff) just in case this somehow was the problem, but no effect.
This ad is not displayed to registered and logged-in members. Register your free account today and become a member on Dodge Forums!
Thanks for your reference to the service manual. I downloaded it and spent a good 2 hours looking for anything at all referencing the rear isolation solenoid, but there is nothing. I guess AllData's diagrams aren't so incomplete after all, because it has all the same diagrams as the Service Manual.
All the electrical diagrams related to ABS end at the CAB (Controller Antilock Brakes) and have no mention of the isolation valve solenoid. I checked connector views for the CAB and none of the pins show that solenoid. I even checked diagrams for RWAL (rear antilock brake) and there's no reference to that solenoid, but I know it exists. I've seen pictures of the solenoid and someone had posted the specs for testing.
So frustrating. Does anyone even know where the rear isolation valve solenoid is located on a 4 wheel antilock equipped truck?
ZMAN17... When I read using an ABS scanner, code 53 is what comes up. (Photo attached.) Is there some reason you know 0f that it's not supposed to come up on a '99?
HEYYOU... Isn't this the official workshop manual, the same one Dodge techs use as reference? I can understand y it wouldn't be listed in an owner's manual, but the shop manual? The controller is separate from the part that holds the solenoid. It's not the issue. The controller's doing its job by reporting there's a short circuit in the solenoid. The issue is either wiring or the solenoid. A tech would want to verify the solenoid is the actual problem before he makes a customer spend $1000 on the entire unit, only to find out it's a wiring issue. Problem is I can't get enough info to test neither. The part obviously exists. People have found specs and been able to test this part and its wiring on RWAL trucks and it's not identified in this shop manual neither. I'm just hoping for someone, maybe a Dodge tech with more resources than we have, to chime in with this info.
You are correct. The service manual has a distinct lack of specific information here. Unfortunately, there is a second book as well, the Diagnostics Manual, which we don't seem to be able to find anywhere. (you can find them on ebay, if you want to buy one....)
I only have RWAL on my truck, and the solenoids are in a little block, down by the drivers feet, below the master cylinder. Now, bear in mind, I am basing this off of what I know about GM anti-lock systems..... but, on those, all the solenoids, pump, etc, are in a self contained unit, that the dealer does NOT service. If it fails for any reason, the whole thing gets replaced. If you are SURE that the rear solenoid block is a separate piece, just follow the rear brake lines. Gotta be on there somewhere.
After some more research, I found my answer on a Chevy forum. They also use Kelsey-Hayes ABS units. On 4WAL / AWAL ABS equipped trucks, all 3 isolation solenoids (2 front & 1 rear) are located in the same unit that houses the ABS pump. The ABS controller (CAB) is mounted on top of that unit.
I originally wanted to test the rear solenoid to see if it could be a wiring problem between the solenoid and the controller. But being that the controller is mounted right on top of the solenoids, there would be no use doing this test because there's either no wiring between the two or if there was, it would be 1 or 2 inches long. So, I guess I'm off to find a new / used ABS unit.
Thanks to those who replied.
BTW, this is the slowest loading discussion forum site ever! It must be all those advertisements.