How to troubleshoot speedometer?

[all-wheel-drive]

I have looked around a bit, but i'm unsure exactly how to troubleshoot my speedometer so that I know what's wrong with it. I am currently restoring my 91 325ix, but after letting it sit for about 2-3 weeks with the battery disconnected (i'm installing a new stereo), the speedometer no longer registers my speed no matter how fast the car is moving. It worked just fine the last time I drove it (the day I disconnected the battery), but suddenly quit working. Is there a way I can troubleshoot what is causing the problem? Is the problem obvious and i'm just not seeing it? Any help is appreciated.

[ForcedFirebird]

Check if the sensor on the differential is plugged in. The plastic like to break on them from age and will occasionally come disconnected.

[all-wheel-drive]

Thanks for the response. The plug is snug and secure in the differential. I think it may have something to do with the fact that there's no stereo in it? I read that the stereo and speedometer are connected due to the way they are wired.

[Gregs///M]

fuses

[dogsbark26]

Welcome to the forum. Where in the midwest are you?

What else have you molested? Did you disconnect the OBC when installing the radio? Did you remove the speedometer from the cluster? The pins are delicate when plugging it back into the main circuit board of the cluster.

First follow Gregs///M's advice and check fuses.
Then unplug and plug back in each connector on back of cluster.
If all else fails, try a different speedometer in the cluster.

The lack of stereo will not effect the speedometer.

[Poorboyz]

I was going to give my opinion but then saw Gregs///M had replied...lol

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