ducklaw

I have a '82 4000s. Speedometer quit working. Where do I start? I see the speedometer thing under the hood, is that the first thing to replace?

ledzepp2994

Before you start replacing things i have seen the plastic collar that holds the cable in to the dash get old and break. check back there if that is the case the cable could have come off up there.

ducklaw

...before it stopped working it was ticking pretty loudly at times, and the speedometer needle would bounce at very slow speeds.

Rogviler

It sounds like what I had. The cables are in a pretty vulnerable spot and water loves to get into the sheathing, so the one on my car eventually rusted and broke. The place where it broke still turned for awhile, and it would tick and bounce, especially when it was cold. Finally it quit completely.

I would first check the cable that runs from the box down to the transmission, as it's the easiest to remove. It's also the most likely to go bad since it's more exposed and water can run down into it. Turn one end and see if the other end turns or not or feels sticky. If it's fine then check the other cable that goes to the cluster.

If the cables check out, it's going to be either the connection at the cluster as mentioned above, the box under the hood, or the gear in the transmission. Thankfully these are pretty simple, unlike the later years where it's all electronic.

But I will bet a dollar that it's the engine bay cable.

-Rog

ducklaw

Wow...thank you so much. Really helpful. I'll look at it tonight. As a follow up? How does this system function? Something turns at the transmission, that turns the cable, which turns something in the box under the hood, which turns the speedometer????

Rogviler

Basically you can look at it as just a simple cable system like they've had on cars since the beginning, which more or less connects the drive speed directly to the gauge. All analog. I completely space what the box does that the cable goes in and out of under the hood, but I'm sure it's just feeding info to the computer.

They're nice because they're fairly bulletproof. The later electronic ones can be a nightmare to diagnose. It's just annoying that they put that box right where rain can get into the cables (especially if your flimsy plastic cover is cracked).

-Rog

4corners

miles counter for oxygen sensor and light reset

Rogviler

I knew it was some kind of counter...

Interestingly, my '85 just has a cable that goes straight from the trans to the gauge, so I guess they did away with them after '84. Seems much more reliable that way.

-Rog

4corners

After '84 they went to the single cable and put the counter and reset behind the instrument cluster.