The gear indicator lights on my truck were acting up, and this is why.
As I would move my shifter through the gears, it would hit each detent and engage the correct gear, but the indicator lights on the dashboard told a different story. It felt like more of a mechanical problem than an electronic one, so I crawled underneath to check it out.
As an assistant moved the shifter, I watched the linkage move, and saw a little bit of play between the manual shaft (that which the shift linkage turns to open/close valves and work the parking pawl) and the inner collar of this switch assembly. Not something that could be fixed by adjusting the mounting position of the switch.
Some call it a “neutral safety switch”, others call it a “back-up light switch”, but it does more than that, sensing each shifter position and activating and deactivating different circuits to control the truck’s ability to start, as well as exterior and interior lamps. Another term I’ve heard, “range sensor” seems to fit rather nicely, although I can’t make up my mind whether “sensor” or “switch” more accurately describes its function. But I digress...
I picked up a new one from the local Carquest and started to remove the old one. I unplugged the connectors, removed the manual shaft nut, and sitting behind one of the mounting ears was a lonely bolt. I don’t know how it hadn’t fallen off onto the road by now, or where it even came from, but it must have been sitting on the transmission case flange since before I even bought the truck. Scary.
Anyway, I changed out the range sensor/switch, and the new on fit nice and tightly over the shaft, allowing the shaft to turn that little plastic collar with much more precision. All the dash lights now work as they should, but I think the best part is that I caught it before it gave me a no-start scenario. That’s a win right there.