Black box behind the dash?

[dnb]

WHat does the little black box behind the dash actually do? It seems to connect to the speedo, but then the wires disappear into the loom and are never seen again.

Presumably it's some form of signal conditioning for the speedo?

[simpo two]

Just put the dash back quietly and move on

[Polarbert]

^^^ It probably fell off!




Please note this is a joke

[raw-sewedge]

dnb said:

WHat does the little black box behind the dash actually do?

This is normally how a long spell of pain and expense starts

[dnb]

I'm already in to the long spell of pain and expense... (New rad, ECU, fuseboard, alarm, heater controls, wiring, fuel pressure reg, injectors etc.) I just want to know if the little black box connected to the speedo is necessary for working the speedo or if it does something else. If it doesn't do anything for me then it gets binned.

[banana man]

the little black box attached to the speedo tells the ecu that the car is moving and how fast its moving to control the revs as such hope this helps????????

[dnb]

Thanks. I guess I don't need it then!

[shpub]

banana man said:

the little black box attached to the speedo tells the ecu that the car is moving and how fast its moving to control the revs as such hope this helps????????

I doubt it as the speedo sensor is hooked directly to the ECU. There is on some cars a box that converts the pulses from the sensor so that the speedo works correctly. I would leave it be on the grounds that if it ain't what is name, the flagpole will fall over while chasing a rabbit...

[chevtrev]

I have a dash dismantled,so will trace and let you know tommorrow.

[stringbag]

If I remember correctly, there was a black box for the immobiliser in there when I took my dash out.

[FlipFlopGriff]

Immobiliser box definately. I think there is another which I think is also alarm related. I'd forget about it until it goes wrong.
FFG

[beano500]

Might be that a previous owner just popped a few bits and bobs behind the dash to confuse anyone brave enough to strip the dash out.......

[JonRB]

beano500 said:

Might be that a previous owner just popped a few bits and bobs behind the dash to confuse anyone brave enough to strip the dash out.......

Only your twisted mind could come up with that, Ron.

[dnb]

Worryingly, Ron was the previous owner...
Would you like to tell me something Ron?

Definitely NOT the alarm. This is in a nice metal silver box these days (the old one was indeed 2 little black boxes, but they didn't connect to the speedo). It's not the heater controls either.

The wires that go into "my" black box are power, blue speedo wire, earth and a couple of others. I'm inclined to agree with Steve that it is some form of speedo signal conditioning.

My real problem is that now all the new kit is in the car, I have far too many apparently redundant wires to deal with.

[chevtrev]

I traced back the black box wires today,they go to both lights at the bottom of the speedo gauge,haven't got any cars going at the mo,do these function as anything?