I shorted it directly to the negative terminal of the battery with a long wire.

As a novice myself, I can only relay my experience, which is that I turned the key on, and then made certain I had the orientation of the OBD2 reader correct in my brain, and then made sure I counted from the correct side 9 .. 10 .. 11 .. 12 .. 13. In fact, when I looked very closely, it actually looked like pins 10 and 12 were blank ( but I didn't verify this ). I did see the shiny metal connector in pin 13. I took a solid piece of shielded 12 g copper, and flattened the one exposed end to form a blade so I could slide it in easily. While I usually prefer when it slides in with some resistance, I slid this one in without and was not upset. I held it there for 2 seconds, and after that time it started flashing and I pulled the wire out. I also noticed that the ABS light kept flashing after I shut the key off and then turned it back on. That is .. it was still displaying the diagnostic mode I guess. The light was not flashing when I had the key in the "off" position.

.. and that's how I got 'er to flash me !

Perhaps there is some significant difference from '96 to '98 ? Assuming you also have the RWAL ?

 

I only see one long one short which would make it 2 "open in the isolation valve circuit" but the troubleshooting is the same for both valves. Basically check all the connectors at the CAB (controller antilock brakes) and the ground. My truck every once in a while throws an ABS circuit code and removing the connectors, spraying them with contact cleaner and clearing the code fixes it. In your case you might need to check the resistance of the valve solenoid, should be 3-6 ohms according to the FSM.

There is, in 98 the RWAL controller talks on the CCD bus and can be read with a proper scan tool. Unfortunately the typical auto store scan tool can not do this.

 

ARGH !!! THANK YOU for watching that !! YES -- You are right ! One long and then one short and then the next one is long again, restarting the cycle ! DOH !!!! i m dum.

Two flashes :
2 Open Isolation Valve wiring or Bad Control Module

I will clean the connectors and then reset the code and see what happens.

You suggest that I might need to check the resistance of the valve solenoid, and that it should be 3-6 Ohm. Is there a written procedure for this ? Where to connect each lead of the ohms testing device and such ? I see people referring to this FSM (Factory Service Manual ), and I hear that it is posted somewhere here on this forum, but I've not been able to navigate to it ?

Thanks so much for watching that video and confirming that I screwed up !

 

Your older truck is quite different from my 2001 so I can only go by the FSM. The "CAB" is somewhere under the dash and has a 14 pin connector. Pins 1 (light green/white wire) and 8 (white) go to the solenoids and their common ground is on pin 10 (black/orange). Just use an ohm meter between the pin 1 or 8 and ground pin 10. Pin 1 is the isolation solenoid in question but having a comparison with the other solenoid might be helpful. There is also a 4 pin connector at the valve block where you could check the solenoids directly but with the drawback that it omits the wiring. To make it more difficult the wiring color is different for the ground, the FSM shows black and pink. The solenoid wire colors are as described above.

FSM are here : https://dodgeforum.com/forum/2nd-gen...e-manuals.html

 

Thanks for that link; very helpful.

I had located the CAB controller even prior to my posting, and to verify that it was the module for the ABS, I had done a simple connectivity test; i.e. "buzzed" the wires. I connected one end of the buzzer to the 4 hole wired connector at the ABS valve, and the other to the pins on the connector after disconnecting it from the CAB. I wanted to just make sure I was examining the correct module. 3/4 wires had good strong buzz ( I didn't check for infinite Ohms, I was just trying to establish if there was a completely broken wire or something ). The 4th wire which connects to the ABS valve did not correspond to any wire / pin on the connector under the dash. My thought at the time was that it may be a ground wire which goes somewhere else. The wires under the hood at that connector are pretty faded and difficult to tell what the colors are.

Tonight when I get home I will examine the FSM and really get an understanding of which wires under the hood should be connected to which pins on the connector under the dash. I will see if I can do the Ohm test on the ABS Valve itself, and I would like to be able to do the Ohm test on the CAB until itself, but it is extremely difficult to remove. (2/3 screws seems easy but the 3rd screw has barely any room to get any kind of tool in there). I'll do those tests last if I have to.

Many thanks for the information, and I'm looking forward to getting these results !

 

I don't think there is any use testing the CAB itself. Check the solenoids directly at the valve block, then the wiring between the CAB and the valve block.

 

Yes, the sensor on the top of the pig.

 

I had this same issue

 

I took this screen shot from the FSM.

According to this, at the ABS Valve, the Z8 Circuit ( Black with Pink wire ) goes directly to ground. Should I take that at face value ? Let me put it another way. I put my volt meter positive lead on the positive terminal of the battery and I stuck the negative lead of the voltmeter into the connector where the Black/ Pink wire is. Nothing. If that wire goes directly to ground as I believe, then shouldn't I be getting voltage when I test in that way ? If I'm not getting ground to that ABS valve through that wire, could that be part ( or all of the problem ? ). Just posting as this is what I've discovered so far. I'm going to continue reading and studying the FSM to see what I might be missing.

( Also I notice that, according to the diagram, the Isolation valve is first inline for getting ground through this wire, which is another reason I suspect that the root of the problem is that this wire does not have proper ground some how ).

 

This ( 8W - 15 - 9 ) as indicated in the in the previous post above .. seems to show that BK / PK wire for RWAL also just going directly to ground as I don't think that these splices exist since my truck only has RWAL and not "ABS".

more evidence that there should be ground on there.




It is funny .. in other pictures where I see "G107" I see it around the 4WD indicator light. That light is also NOT working for me right now, although I do believe that the 4WD is actually engaging. The evidence for this is that when I pull the shifter into 4WD, and put the transmission in drive, all 4 wheels spin. ( I have the truck completely elevated with the wheels off and can see all the hubs spinning ). Perhaps this is another clue that it is a ground issue with the G107 circuit ?