944 Odometer Trip Reset Solenoid

[DJOTron]

Confirmed - 3.4 Ω between the ring connectors (yay!).

I like your idea of using the cigarette lighter - I’ve got plenty of 15-amp fuses on hand. Here’s a pic of my setup: I verified that the center wire (white/black) from the 12 V adapter is positive, and the solid black is negative. The negative/black alligator clip is connected to the bottom ring connector.

The plan is:
1. Plug the 12 V adapter into the cigarette lighter, making sure the alligator clips don’t touch (I’ll probably tape them off for safety).
2. Since the cigarette lighter is always hot, I’ll momentarily touch the positive alligator clip to the top ring connector and see if the solenoid activates and the trip meter resets to zero.

If the solenoid doesn’t respond, I’ll order a replacement. If it does, I’ll move on to testing the Trip Odometer Reset Button Switch and/or the wiring leading back to the gauge cluster.

Let me know if you think I’ve missed anything before I give it a try.

[Tom]

Sounds good to me. If the solenoid doesn't work, there's a slight change the plunger part just isn't able to move for some reason. So, before ordering a new solenoid, I'd take yours out and power it up out of the cluster so you can confirm it's not making a magnetic field.

[DJOTron]

Success! The trip meter reset to zero as soon as I applied 12V positive to the top ring connector.
I then disconnected the trip meter switch and confirmed it’s working (continuity when the button is pressed).
I was able to confirm continuity from the brown/yellow wire inside the connector, to pin 17 inside the harness.
When testing the red/yellow wire from inside the connector to pins inside the harness, I’m getting continuity on pins 1, 2, 4, 5, 6, 7, 10, 13, 16. Does that sound correct? If so, could this come down to a poor connection of pin 17 between the harness and the circuit board?

[Tom]

Let me get out my test rig and give you some continuity points to check. The electrical traces can crack and fail on the cluster's blue flexible circuit board. I had a boost gauge that refused to work and I finally trace if back to cracked runs on that circuit board. The good news is it works. Now it's just a matter of figuring out where you are losing the signal.

[Tom]

The top ring connector gets its power from Pin 13 on the B connector, which should be a black wire with yellow stripe. That wire is at 12 volts all the time when the ignition is on (meaning the top ring connector should have 12 volts whenever the ignition is on). The bottom ring connector gets ground from pin 17 on the B connector, which should be brown with a yellow stripe. That ground signal is the one going through the button switch. The red/yellow wire going to the button switch is hard-wired to ground (admittedly with counter-intuitive colors for most of us). When the button is pushed, it supplies ground to the brown/yellow wire, which goes to Pin 17 of the edge connector and to the bottom ring connector on the back of the cluster, thereby activating the solenoid.

Your problem is either in the cluster or in the harness. To figure out which one, try to power the solenoid with 12 volts again, but this time, instead of using the ring connectors, apply 12 volts to Pin 13 of the B edge connector on the cluster, and ground to pin 17. If the solenoid activates, the cluster is good, and the problem is in the harness. If the solenoid does not activate, the problem is in the cluster circuit board. Let's start with that, and we can then work backwards from there to pinpoint where the issue is.

cluster-check.jpg (925.08 KiB) Viewed 1552 times

[DJOTron]

Test complete - applying 12V positive to Pin 13 and negative to Pin 17 activated the trip reset solenoid perfectly

[Tom]

Test complete - applying 12V positive to Pin 13 and negative to Pin 17 activated the trip reset solenoid perfectly

I'd take that as good news. It means the cluster is fine, which is good because it can be a real chore to patch broken traces on those flexible circuit boards.

At this point, either (a) you are not getting 12 volts on pin 13 when the ignition is on, or (b) you are not getting ground to pin 17 when the button is pushed. (Or I guess there's a remote chance neither is working.) As such, the next tests I'd suggest are:

1. With the ignition on, and the cluster out of the car, check for 12 volts (battery voltage) on Pin 13 of the B connector. Set the multimeter to DC volts, and touch the red lead to the Pin 13 contact in the connector, and touch the black lead to chassis ground. You should see 12 volts (battery voltage). If you don't, then we'll need to trace that signal to see where it's losing power. If you are not familiar with testing for voltage, you can practice on any household battery.

2. Pull the connector off the reset button/switch, and test that the contact for the red/yellow wire has continuity to chassis ground. If it doesn't, then we'll need to trace that signal to see why it's not grounded. Next, confirm that there is continuity between Pin 17 in the B connector, and the contact inside the button/switch connector for the brown/yellow wire. If it doesn't, then there is a break in that brown/yellow wire between the button/switch and the cluster.

Try that and let us know what you find. We're almost there...

[DJOTron]

Confirmed: With ignition on, Pin 13 of the B connector shows 12 volts (battery voltage).
Confirmed: With the reset button/switch removed, the red/yellow wire inside the connector has continuity to chassis ground.
Confirmed (with concern): I verified continuity from the brown/yellow wire inside the connector to Pin 17 in the harness. (This was also confirmed in my post on Sat., Aug 9, 2025, with the included image.) However, I suspect it’s not making a solid connection when connected to the circuit board.

I’ve attached photos of the inside of the B connector. The top pin is recessed when compared to the others. I’ve included shots from multiple angles to highlight both the top and bottom pins inside the connector. Hopefully the images make the misalignment clear. @Tom - Thoughts on next step(s)?

[Tom]

The pin inside that connector is probably mangled or pushed out of shape. If so, I can do a video showing how to remove it, and I'm sure I have a spare I could offer if needed. To confirm that's the issue, put the B connector back on the cluster, and check for continuity between the brown/yellow wire in the reset switch connector and the bottom ring connector behind the solenoid. You've already confirmed continuity from the brown/yellow at the switch to pin 17 in the B connector; and continuity from pin 17 of that edge connector to the bottom ring connector; so if you do not have continuity all the way from the brown/yellow wire at the switch to the bottom ring connector, then the B connector must be the issue.

[DJOTron]

Final Update: I ended up carefully tightening the gap between the top and bottom pins (pin 17), reinstalled the cluster, and bingo - the trip reset works! @Tom - Huge thank you for your guidance in testing the different possibilities. I’m glad the issue is resolved, and hopefully this thread will help someone else troubleshoot their own trip reset woes.