What is this thing? (pic inside)

[Frog]

This is plugged into the back of the speedometer behind the cluster. What is it? Does it matter which way it is plugged? the two prongs are identical with no markings.

[E30SPDFRK]

Wire tap

[Court M3]

Damn never noticed that. Pic of actual location?

[TobyB]

The matrix is tapping into your car's brain.

t

[Frog]

Where it goes:

[Gregs///M]

Yup, its a jumper for the circuit board of the speedo. Not sure its intention, but you can plug it in any orientation.

Only the older white backed clusters have this.

[Frog]

How do i test if it works?

My speedo doesn't work. My odo doesnt work. I have replaced the gears, replaced the batteries.

My speedo randomly started working during one test drive for half a minute. Not sure what is wrong.

[Gregs///M]

How do i test if it works?

My speedo doesn't work. My odo doesnt work. I have replaced the gears, replaced the batteries.

My speedo randomly started working during one test drive for half a minute. Not sure what is wrong.

Could be a cracked solder joint on the cluster main board. Or your speed sensor in the rear differential. Check the connector first and make sure its not loose or damaged.

[Frog]

Could be a cracked solder joint on the cluster main board. Or your speed sensor in the rear differential. Check the connector first and make sure its not loose or damaged.

I forgot to mention one of the resistors was burnt. So I went to Frys and got me one that appears close (hard to tell the colors since it's burnt). Replaced it. Looked over all the welds but they all seamed fine.

[Frog]

Ok, so here are the symptoms:

The cluster sometimes work beautifully with no issues. The MPG gauge works, temp, fuel, the tac is stable, the speedo works, and the odometer works. Works maybe 10% of the time. It will suddenly start working and then just as quickly stop working.

When it is not working (which is most of the time) the MPG gauge is dead, the speedo is dead, the odo does not work. The TAC also appears to be shaky. Temp and fuel work.

Is this a board issue? What goes through the Si Board?

[Ferdinand]

See this post: http://www.r3vlimited.com/board/show...5&postcount=26

[RGCintha29073]

See this post: http://www.r3vlimited.com/board/show...5&postcount=26

+1 Had the problems you describe in my e24, and i replaced the board, the speedo and the gears. Only after reflowing all the solder joints here as described did the problem go away. Not it works 100% of the time.

[AlphaE]

"I forgot to mention one of the resistors was burnt. So I went to Frys and got me one that appears close (hard to tell the colors since it's burnt). Replaced it. Looked over all the welds but they all seamed fine."

"appears to be close" isnt good enough when it comes to electronics. Even if you reluxed all the solder joints this "close" resistor could still jack you up. Best bet is to find another cluster and ohm out the resistor in question. Sounds like refluxing it cant hurt.

Hope you figure it out.

[Frog]

^yeah, I am afraid that could be the issue. I will post pic of which resistor it is and hopefully someone can tell me the ohm.