Corsa Display only at night

Check that the display is getting a feed on the black wire, which is fed from the ignition switch. There is a fuse in the circuit that may have blown (F17) which is marked KL15 on the fuse box lid.

If this supply is OK, then I expect that there is a problem with the display itself.

HTH

Anthony Remove eight from email to reply.

if it works with a thump then the internal connector to the circuit board is probably loose, I have soldered these up before with good results.

mrcheerful

Not trying to be funny, but does the Corsa have a dimmer for the dash lights like the Astra?

Thanks for the replies

I checked the black wire from the ignition switch all the way to the actual track on the PCB and get the 12v OK, can we be sure this is for illumination?

I also checked the Grey with Black tracer wire which is from the spedo illumination (via the dimmer potentiometer) This goes through a large surface mount resistor then a large wirewound 10 ohm resistor then onto the bulbs. this works fine.

Also on the clock PCB is a small 2A PNP transistor (FZT 753) the collector of this is connected to the bulbs, the emitter is connected to the clock red wire which is a permenent 12V feed (even with ignition off, this 12V reads OK on the emitter). So I am assuming that when the ignition is on (Black wire live) there should be a signal to the base of the transistor to illuminate the clock during daytime. Then when side lights are ON the transistor switched OFF to allow the potentiometer (dimmer) to control the illumination.

Before I started this I was almost convinced this was to do with the non-factory radio but it now looks like a fault on the clock PCB.

Another question before I go further into this, during day (no sidelights on) how bright should the clock be compared to when the sidelights are on (with dimmer on max)??

Thanks again

Thanks for the reply. Yes it does, see post above, I was slow at typing :-)

Regards

With the dimmer in the maximum illumination position, there should be little difference in the brightness of the display between day and night (lights on) position.

HTH

Anthony Remove eight from email to reply.

Thanks for the replies, I got it sorted now.

Here was the problem for info.

I unsoldered the 2A transistor (FZT 753) and checked it with a meter, it was totally open circuit from Emitter to Base. A new transistor from a local electronics shop was 85 pence. Fitted this and now works great. Answering my own last question, when the ignition is on the clock is at full brightness, when sidelights are switched on the brightness roughly half's (with dimmer on full).

So the clock lights rely on this transistor for daytime illumination (approx 1.8V on the base of the transistor) switched by the black ignition wire signal (but actual votlage to the bulbs supplied by the red wire via the transistor). Then when sidelights are ON the transistor is switched off and the bulbs powered by the Gray with Black tracer wire (normal spedo lights via potentiometer)

Only other thing to add that caused confusion is when the clock has been totally disconnected in this way, upon re-connection it will PERMANTLY illuminate (ie even with ignition off) until the clock time has been reset, then will function correctly off the ignition key.

Thanks again

The message from snipped-for-privacy@spam.com contains these words:

You'll probably find that was an illegal modification to a registered design and the thought police will be round shortly.

Worse, you've compounded the offense by describing parts of the circuit to us, so we're all for a trip to the slammer as well.

best tell the insurance company too

Oh! I see this group has 2 of them?