Well, after pulling my steering wheel and making sure to recenter the clock spring. I did an ohm test (and forgot to actually check numbers), but all the switches cause resistance, so the switches "work" and the clockspring is fine. I did note one ohm resistance is the on button, it was reading about .45 ohms instead of 0. Although I would assume this should still be within tolerance. Outside of this testing, I tried to check the brake switch signal wire at the servo connector (Dark Blue/Red), and no matter what I tried could not get voltage to show. Playing with the brake pedal, tapping on/off, pulling the brake switch out and manually depressing it, nothing. However, if I probed the servo solenoid wires, I got a steady .02V. Since my cruise light is turned off in the PCM, I cannot tell if either A: The PCM isn't turning on the cruise or B: brake switch is just not sending current. I did note, however, that my brake switch harness does not have the DB/RD wire that I see at the servo side, although I may have just missed it. Hindsight is 20/20 so I never think to check until I put it back and kick myself in the head and have to pull it back apart.

EDIT: Took the brake switch out and tested it, I get continuity everywhere it's supposed to. Noted there is indeed a DB/RD wire in the harness... Guess I gotta try to find a run of wire to test continuity there.

 

you'll always have resistance due to the bias resistor in the right pad. The circuit is never truly open nor shorted.

1. static bias resistor
2. on/off resistor parallel to bias resistor
3. set resistor parallel to bias resistor
4. coast resistor parallel to bias resistor
5. Resume/Accel resistor parallel to bias resistor
6. Cancel resistor parallel to bias resistor.

 

Brake switch checks out, ohms check out through the clock spring on all the switches, continuity from the brake switch signal to the servo harness is good... Everything seems fine, just the PCM is not turning on the cruise when signaled is my guess. What wires would I check for voltage when the cruise is "on"?

 

You have the vacuum reference hooked up to the servo, yes?

The PCM pulses both solenoids with a PWM signal to maintain the vacuum reference on the diaphragm servo. You're unlikely to actually measure a voltage.

 

I think this issue might have to wait until I get around to turning the cruise light on. Therefor I can actually tell if the system is being powered or not.

 

Hm, I might have figured something out. I did my math wrong, I was using 20k setting on my voltmeter for ohms, and I was getting .45 for the on button, I multiplied by 100 and not 1k, so my on switch is actually sending 450 ohms, which I assume is actually out of spec. Does this seem plausible to anyone?

EDIT: Apparently I was thinking wrong on the ohm settings. I found a 2carpros link for a 1998 Dodge Ram, which should have about the same system as my 1998 Dodge Dakota (should...) It lists the values as follows, which still means wrong with what I got for on/off.

On = 909 ohms
Set = 6650 ohms
Resume = 15,400 ohms
Cancel = 0 ohms
Coast = 2940 ohms

I'll have to take my column bezel back off to test, but I'll see if any other switch matches these numbers, and if they do, I may just need a new left-side switch. If these are wrong, does anyone have the proper resistance numbers? I can't seem to find it in the 2k fsm (which is the closest I could find to my 98) Can't find it in my chilton's book either.

 

no way in heil that cancel is 0 ohms....

I have the buttons and harness from my donor column somewhere. I'll see if I can play with them.

 

I'm sure it likely had about a 100 ohm window, but still 450 isn'tclose to 900.

Edit: Found the numbers in the stratus section as well, however, they list on/off and cancel as the opposite. 0 for on/off and 909 for cancel. I'll have to retest and actually write down my results later to see if anything matches up. I'm thinking, if it is supposed to be near 0 (compensating for system resistance) then the contacts are dirty, creating extra resistance (going by my 450 ohms reading). Flipside, if on is supposed to be at 909, then it's resistor degradation allowing too much current. I'm hoping it's simply a bad switch, I did get it from a junkyard truck with an open window after all.

 

Took the multimeter to my truck during lunch at work, reading ohms through the clockspring I get

On/Off: 450
Set: 4330
Accel/Resume: 8780
Cancel: 1160
Coast: 2560

The coast button was very finicky and I had to press fairly hard near the inside to get it to remain steady. I also probed the signal wire to the clockspring for the cruise, tested with the ground in the harness, and body ground, both have a consistant 2.98V, I thought it was supposed to be a 5V signal? I also managed to find the wiring diagram for a 1998 dakota, all the wire colors match up and everything in my tests seem alright, although the resistance is a bit all over the place. From the numbers I found:

On/Off: (if 0) +450 (if 909) -359
Set: -2320
Accel/Resume: -6620
Cancel: (if 0) 1160 (if 909) +251
Coast: -380

Listing differences between "intended" and my own results, most of them seem to be reading quite low except cancel, which is higher both ways. Along with the steady 2.98V on the signal wire, I'm a bit stumped. This voltage is consistent with ignition on, engine off, and ignition on, engine on. I still can't find any concrete evidence on what these values should be for a 98 dakota, but what I listed above seems to be fairly standard. My only guess on the voltage is it has 2.98V, but pressing "on" should ground that signal wire, telling the PCM to boost to 5V (turning the system on), then it reads the load differences of the switches to determine which button was pressed. Whereas if it receives a full load (0~ ohms) it turns the system off. This is only me guessing but trying to figure out how the system actually works.

Posting the Wiring diagram for others:

 

I think you should be seeing a 5 volt reference signal......

Does the brake switch BREAK that circuit when you step on the pedal?