Bouncing speedo? No "ping" when drivers door open???

So, been a few years since Ive really driven my fox mustang on a regular basis. Over the last week I've been daily driving it and have noticed a few small issues...

1) My speedo needle is bouncing all over the place. I do have 3:55 rear gears and 17" wheels on it, which explains the speed not reading right, but bouncing needle?? Do I just need a new speedo cable?

2) When I open my driver or passenger doors, the dome light doesn't turn on. It turns on when I open the rear hatch, just not the doors. Also, I noticed there's no "Bing" when the driver door is open and the ignition key is turn on?? What would cause this??

3) My rear plate lights don't illuminate. All the other lights work fine, just not the plate lights. I put new bulbs in, I'm thinking its a wiring issue. Any suggestions on where to start looking??

4) So after hitting a few potholes driving around the fantastic roads we have downtown here (NOT!!!), I need to get the rear fender lips rolled so I don't mess up my tires. Do people get the front fenders rolled as well?? I know it's common for the rear fenders, but should I do the front fenders as well?

Thanks for any input! Its been interesting rediscovering the old mustang to say the least!

Speedo jumping is a cable issue, swap it out, doors are likely the door switches, they can go bad or you may have a wiring issue, plate lights sounds like a wiring issue, front fenders are slightly rolled from the factory, and there’s no point trying to roll them more, you’d be better off stretching them out if you really need the additional room.
Also, what year fox and is it a hatch or coupe?

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Originally Posted by Ponyryd

Speedo jumping is a cable issue, swap it out, doors are likely the door switches, they can go bad or you may have a wiring issue, plate lights sounds like a wiring issue, front fenders are slightly rolled from the factory, and there’s no point trying to roll them more, you’d be better off stretching them out if you really need the additional room.
Also, what year fox and is it a hatch or coupe?

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Its a 1990 hatch. 5.0L 5spd.

There are door switches for each door, in the front door post, just below the door harness, take the switch out and disconnect it, watch for a change.
The licence plate lights may be due to bad wiring in the hatch harness where the harness comes through the hatch from the body, you can try wiggling the harness while watching for the lights to come on, but most likely the wires are cut........does your third brake light work?

Quote:

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Originally Posted by Ponyryd

There are door switches for each door, in the front door post, just below the door harness, take the switch out and disconnect it, watch for a change.
The licence plate lights may be due to bad wiring in the hatch harness where the harness comes through the hatch from the body, you can try wiggling the harness while watching for the lights to come on, but most likely the wires are cut........does your third brake light work?

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I tried having a look for the door switches but i couldn't see anything at all. Not sure if I just wasn't looking hard enough or if maybe when the car was repainted a few years back, they were never reinstalled? I dunno. Unfortunately this mustang has seen many owners and shops. The third brake light does work, yes. Checked the bulbs, they look good. Might just change them again to be sure.

In the forward door post (a-post) is where they should be, right in the middle between the hinges, just below the seam . If they aren’t there that would make sense, but there should be a plug or hole there then.
Regarding the licence plate lights, if you have a test light just check for power and ground at the bulb sockets.