Overdrive switch inoperable?

Tiny
DAVID ENDACOTT
  • MEMBER
  • 1996 DODGE VAN
  • 5.2L
  • V8
  • 2WD
  • AUTOMATIC
  • 186,000 MILES
Hello. The overdrive switch, located on the dash, left side of the steering column, lights up when engaged, yet has no effect now. This happened once before, and it ended up being a relay under the hood. I have replaced that relay once again, but this time it did not solve the problem. It's either that or my transmission doesn't shift into fourth. The switch light is operable and the vehicle is not in limp mode, I don't think. At least it's not acting the way it did the last time it was in limp mode when the relay was bad. I've had the van since it was brand new in 1996. Could you possibly point me in the right direction as to what I can do to perhaps repair this before I'm forced to take it to a shop? I can read a schematic and I understand wiring diagrams. I'm not afraid to get my hands dirty and I have test equipment. I also know when I'm out of my depth. Please help if you can. Thank you very much in advance.
Sunday, June 15th, 2025 AT 4:38 AM

11 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,136 POSTS
Hi Dave,

I suspect you checked things such as the trans fluid and its condition. Have you tried scanning the computer to see if any diagnostic trouble codes may point us in the right direction?

As far as the circuit, OD is actuated via the PCM (powertrain control module). When you activate the switch, a signal is sent to the PCM, which controls the OD control solenoid in the transmission. The PCM makes the determination when to use OD based on vehicle speed and load.

If you look at the transmission where the wiring connection is made, locate an orange wire with a white tracer. That is the wire that signals the control solenoid. Make sure it is in good condition and not corroded or damaged.

Also, I would recommend having the computer scanned to determine if there is a code. Also, check to make sure the ground to the switch (located above the headlight switch) has a good ground. The indicator light is powered via a fuse and grounded via the PCM. The OD control portion of the switch is grounded separately, so you can have a functioning light and not the switch. I attached the schematic below, so you have a reference.

Let me know what you find.

Take care,

Joe

See pic below.
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Sunday, June 15th, 2025 AT 9:20 PM
Tiny
DAVID ENDACOTT
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  • 19 POSTS
Joe, thank you very much. It is extremely late now and I am beat tired. I did take the switch out and check the continuity and all that good stuff and there's momentary continuity or it should be and the light works fine. I will crawl under the thing tomorrow and check the wires that you suggested to make sure that they are in good shape. I don't have a scanner I just have one of those OB 2 reader things that I have to download an app to use. I used it once, but I can't remember what that was all about. I push the overdrive switch in and of course the light comes on but still no joy. I'll check the grounds as you said. I just talked with another one of your folks, a very nice man and very helpful as well, who assisted me with my interior lights not going off when I turn my headlight switch all the way to the right. That problem is solved at last. It involved removing the headlight switch assembly, so I possibly may have messed up a wire in that regard, but I don't recall doing such a thing. I was afraid that I would have to take this to a shop. It's kind of a drag. I had the transmission replaced about 13 years ago. I checked the fluid level and I'm going to add some fluid. If I recall the transmission fluid is red but the stuff that's in there looks like it's clear. Don't hold me to that because like I said I'm very very tired, but I wanted to get back to you and let you know that I received your email. Again, thank you and I'll let you know what I find tomorrow.
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Monday, June 16th, 2025 AT 2:49 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,233 POSTS
JACOBANDNICKOLAS is one of our best! Please let us know how it goes.
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Tuesday, June 17th, 2025 AT 6:29 AM
Tiny
DAVID ENDACOTT
  • MEMBER
  • 19 POSTS
Jacobandnickolas, sorry it's taken so long to get back to you. You asked if I checked the fluid and everything. I pulled the dipstick out and checked, yes. However, this time I actually smelled the fluid and paid attention to the color. I've had this transmission for about 13 years now in this vehicle. I've never once changed the filter or anything, and after going through my manual, it appears that I should have been more diligent in that service. I crawled under the van yesterday and removed the transmission pan. The filter was black, and it should be yellow. Well, maybe not yellow, but it started out yellow. The fluid was a dark color but had a little red in there. Today I'm going to do a flush, and I've ordered the solenoid / filter gasket kit for $200. You know what gets me? When doing the research online about this, I click on my topic, and it shows me pictures of what I want. Here's the problem though: one picture says this will fit your van and it shows a picture. Then you scroll a bit, and you'll see another one that says this will fit your van. But here's the kicker, the pictures are different! They show completely different filters. I've searched by the transmission model number, and description, and everything else Under the Sun that I could think of. Blows me away how they get away with that. Anyway, I decided the only way to make sure was to visually check out what I needed with my own eyes. It should take a day or so for the parts to get here. After I reassemble everything and check it out, I'll give you another update. So please don't close this ticket out yet and I promise I won't forget to get back to you.
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Wednesday, June 18th, 2025 AT 9:41 AM
Tiny
KEN L
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That sounds good, we hope it works out for you.
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Thursday, June 19th, 2025 AT 9:33 AM
Tiny
DAVID ENDACOTT
  • MEMBER
  • 19 POSTS
Talk about frustration. I spent a long time explaining my recent experience to you and uploading a few pictures, only to find that my internet connection had cut out. I had to restart everything. Oh well. I should mention that continuity between the blue/white wire and the green/orange wire pins on the switch is constant, even when the switch is removed. That's most likely due to the bulb. Momentary contact occurs between the orange/white wire and the black wire pins when I engage the switch. I won't bore you with what I had previously written, but suffice it to say, paying attention to transmission service recommendations is a good idea. I have a question: I always place a magnet on my oil pan near the drain plug. I noticed there's a magnet inside the transmission pan. If I placed additional magnets as shown in the picture, would that do any harm?
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Friday, June 20th, 2025 AT 11:35 AM
Tiny
KEN L
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Yep, none too soon on that service, you are okay with having magnet inside the transmission pan. With the new fluid did it perform better?
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Sunday, June 22nd, 2025 AT 11:36 AM
Tiny
DAVID ENDACOTT
  • MEMBER
  • 19 POSTS
Yes! Amazing. Although in the story that follows, there are going to be some bonehead moves that I am fully aware of. However, prior to telling you my story, I would like to ask a question. The rear band adjustment. I loosened the locknut and tightened the adjustment screw finger tight, all the way until it bottomed out then I backed it out two turns and then tighten the lock nut. I haven't touched the adjustment for the bands that are located on the outside of the transmission. I took it for a drive and it appeared normal. It still wasn't shifting into overdrive in the beginning. As I was coming home and getting off the freeway, I hit the button again, I was probably doing about 50, and it downshifted. Don't do a happy dance just yet. When I downshifted, it let me KNOW that it down shifted because I heard, or more accurately felt, the downshift because it was kind of loud and it really worked. I didn't get up to 50 again because I was in town and going home so I don't know what's going to happen next time I do this. I thought I would ask you first. Okay now back to my story. To do the flush, one must disconnect one of the transmission cooler lines and blah blah blah. I found what resembled the transmission cooler going in some videos that I watched. I checked my build sheet to make sure that I had a transmission cooler installed and I do. I tapped into one of the lines that went to the transmission cooler and some transmission fluid came out or I should say some red fluid came out. But it wasn't a lot, but it did look a little dark. I thought maybe I had hooked up the flushing hoses to the incorrect port on the transmission cooler so I put everything back together and checked again via the other port. Still nothing, but I can feel suction on one of the tubes. I finally decided to follow the lines that attached to this supposed transmission cooler. Are you ready for this? Turns out, that cooler is for the power steering pump. I found this out because I fired up the van, and when I turned the steering wheel, it wouldn't budge. Plus, it was whining. And that's when I decided to follow the hoses that I assumed went to the transmission cooler. By the way, the trans cooler is located between the air conditioning condenser and the radiator. I'm guessing now that a flush would be a waste because I was unable to capture what was in the torque converter and that's probably all mixed in with the new fluid now. I know I'm going to have to do the process all over again and by that I mean dropping the pan. But that's cool because if you tell me I need to back that rear band adjustment screw out some more or screw it in some more then it'll be a win-win. But, either way, I know I'm going to have to change the fluid again. I wonder if I'll be able to clean my filter or if I'll have to order another filter? Do you want to know what I'm taking away from all this? I don't know about anybody else, but for me, as I progress in age, I realize that I must start accepting that my brain is weakening and my body isn't in the shape it used to be. LOL. Getting old not fun, if you want to know the truth. It doesn't have to, but it can. I eagerly await your reply.
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Sunday, June 22nd, 2025 AT 1:17 PM
Tiny
KEN L
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On a Dodge there should be a drain plug on the torque converter. So the overdrive works again? I would reuse the filter, it should be okay, you can flush the transmission by removing the fluid return cooler line and let it drain into a bucket while you fill fluid into the fill tube. Do not raise the engine idle. Let me know how it goes ;)
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Monday, June 23rd, 2025 AT 9:08 AM
Tiny
DAVID ENDACOTT
  • MEMBER
  • 19 POSTS
Joe or Ken,
I wrote a long reply, but I don't see it posted here. The bottom line of everything is it works now. I had incorrectly adjusted the rear band adjustment screw after removing the pan. I did a second transmission pan removal to put everything back the way I found it. Because I wasn't able to flush the system, I took the opportunity to replace what fluid I could after repairing my mess. Shifts smooth as melting butter. Goes into and out of overdrive perfectly. I am a happy camper. Thank you very much!
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Tuesday, June 24th, 2025 AT 5:01 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
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That is good to hear, we are here for ya!
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Tuesday, June 24th, 2025 AT 12:20 PM

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