obc help

[bigwinn]

Quick one

Retrofitted obc, functionality is all ok but there isn't a backlight. I've changed the light bar with one I know is good? No joy. What am I missing.

The only wire im unsure aboutis the yellow single plug one

Stu

[Brianmoooore]

Yellow wire with a white plug is unused.
Used light bars can be fragile, so you may have blown this when you fitted it. Confirm that the bar is working by fitting into another car, or by connecting a nine volt battery to the terminals on it, before you start looking deeper for the problem.

[bigwinn]

Checked light bar- works fine

swapped with another VDU unit- backlight not working when installed and was working on other car, so the VDU/lightbar are not at fault

the only other leads/wires I cant account for on the loom are here:



would these not being connected make a difference? They look like they have been taped for a while....

[Brianmoooore]

Only wires that need to be connected for everything except the external temp. and CODE alarm/immobiliser functions to be in full working order are the yellow plug that goes into the instrument cluster and the green one that plugs into the OBC.
There's a bit of circuitry inside the OBC that dims the display when the parking lights are turned on. Your fault is probably with this.

[bigwinn]

tried 3 working vdu units now that work- no joy

so ruled out the vdu and light bar issue-

tried them again in another car and they worked after so im not blowing or damaging the bulbs

[Brianmoooore]

If you've tried three known working complete OBC's and none of them work, then the problem can only be the instrument cluster, or the section of OBC loom that has the green plug at one end and the yellow one at the other.
The relevant wires are the red/white (12 volts permanent live), green/purple (1st ignition switched 12 volts live, green/black (2nd ignition switched 12 volts live) and the brown earth wire.

[bigwinn]

Is there a way of rigging the backlight, by taking a live feed and bridging it into the loom?

Of which plugs on the green plug should I test to see if the light feed is working in the loom?

Stu

[bigwinn]

Bump

[Brianmoooore]

Is there a way of rigging the backlight, by taking a live feed and bridging it into the loom?

No reason why it shouldn't be possible with a bit of bodging, but don't forget that the light bar is rated at 10 volts, so a series resistor or three pin stabiliser will be needed.

Of which plugs on the green plug should I test to see if the light feed is working in the loom?

Stu

Answered in my last post.

[bigwinn]

cheers