98 2500 5.9 no O/D off light in dash

[Clifford98]

Hello, i just bought a 98 2500 club cab with the 5.9l magnum. I noticed my O/D off light in the dash does not light up when I first turn on the key. Also, the OD button doesn't disengage the OD. I pulled the button and jumpered the two connectors with a paperclip and got nothing. I looked at the fuse diagram and don't see any fuse or relay that I think would cause this. I haven't put a multimeter on the switch connectors yet to see if I have any voltage but I think that will be next. I ordered a new switch, but I doubt that's the problem since I don't even get the bulb test in the dash. Any ideas where to start looking?

thanks

 

[Fast69Mopar]

Hello, i just bought a 98 2500 club cab with the 5.9l magnum. I noticed my O/D off light in the dash does not light up when I first turn on the key. Also, the OD button doesn't disengage the OD. I pulled the button and jumpered the two connectors with a paperclip and got nothing. I looked at the fuse diagram and don't see any fuse or relay that I think would cause this. I haven't put a multimeter on the switch connectors yet to see if I have any voltage but I think that will be next. I ordered a new switch, but I doubt that's the problem since I don't even get the bulb test in the dash. Any ideas where to start looking?

thanks

While you are driving, say 60mph, shifter in the "D" position, when you press the O/D button you don't feel the trans downshift from 4th to 3rd and the RPM raise accordingly?

If this is the case and you do not feel the trans downshift from 4th to 3rd and you do not have the O/D Off lamp in the instrument cluster, I suspect a failed TCC/OD on the valve body.

If you go to the connector on the left side of the trans you can measure your voltages here to verify the PCM is doing it's job and that your wiring is good before you drop the pan. Here is the connector pinout...

Pin #1: Red, Transmission Control Relay Output (B+ Battery Volts)

Pin #2: Orange; 5 Volt Supply

Pin #3: Black/Blue; Sensor Ground

Pin #4: Light Green/White; Governor Pressure Signal

Pin #5: Violet/White; Variable Force Solenoid Control

Pin #6: Brown; O/D Solenoid Control

Pin #7: Orange/Black; Converter Clutch Solenoid Control (lock up)

Pin #8: Violet; Trans Temp Sensor Signal.

 

[Clifford98]

correct, I don't feel the trans shift down. does the wiring you mention also provide voltage to the dash bulb and OD switch? I will check this out, thanks for the assist.

 

[Clifford98]

So here's the latest. I tested the OD switch connector and found that I am getting 14 volts. I also received the new switch and it also does not cause the O/D off light to turn on. I'm going to take another test drive and confirm I can't hear the RPMs increase when I hit the button. My daughter's been driving the truck so I'll have to steal it from her for a bit.

 

[Clifford98]

So good news. I stole the truck from my daughter and did a proper test. It turns out my speedometer is out of whack and I wasn't really going fast enough to get into overdrive. So I got it up to at least 60 and then pushed the button and the RPMs did indeed increase after about a second or two. Whew! now I can blow my money on some fun upgrades. I also need to figure out what the heck is up with the speedometer. The tires aren't stock size and I suspect somebody updated the speedometer settings incorrectly. I also need to figure out how to replace the dash lights. I noticed my 4wd light isn't coming on either even though it is working. Time for my next project. I just put some nerf bars on it which was a satisfying project. Maybe a bakflip is next.

 

[scrounge]

I'd advise looking in a junkyard to see how instrument panel lights are replaced. It's not that difficult, but you'll want to make any mistakes on their vehicles that are going to the crusher anyway, not yours. And you can probably find some working replacement lights while you're there.

You'll first need to pull off the plastic bezel. After that, you'll see that the instrument panel is attached with 4 Phillips head screws. You might want to use the tilt-steering to lower the steering column; it's also possible that the transmission lever needs to be put in Low. Unscrew the screws, and pull the instrument panel out. It doesn't (or shouldn't) have a cable for the speedometer; rather, it has a bank of connectors toward the top left. A wire on the lower right will remain attached. From there, you can see where the lower bank of info lights is. Mine have light brown sockets. Replace those you know are burned out, and examine the rest while the panel is off.

 

[Clifford98]

cool, thanks. I saw a youtube video that describes what you are talking about exactly. It looks pretty simple. Thanks for the assist!