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Engine Specific Info and Questions => Diesel Swaps => Topic started by: Smoker on March 12, 2015, 11:22:51 am

Title: AHU mk1 swap with mk3 wiring... questions/issues
Post by: Smoker on March 12, 2015, 11:22:51 am

I put an AHU and O2A in a caddy, using the 'piggyback' wiring method (both mk1 and mk3 fuse blocks intact under the dash).  Everything seems to be working EXCEPT my gauge cluster seems to be dead.  It's getting power, as the clock and odo are lit, but the cluster does nothing.  None of the gauges work at all, none of the warning lights come on when I turn the key.  I have everything from the engine wiring harness plugged into the fuse block (I think??)... I've got to be missing something simple.  Anyone have any ideas??

Title: Re: AHU mk1 swap with mk3 wiring... questions/issues
Post by: RabbitJockey on March 12, 2015, 02:57:08 pm

tough to tell with out really poking around, perhaps you are missing a ground connection or something somewhere?

Title: Re: AHU mk1 swap with mk3 wiring... questions/issues
Post by: Smoker on March 13, 2015, 11:27:58 am

I did some poking around last night.  I found that the harness for the cluster has a few plugs coming off of it that don't plug into the fuse block.  I'm assuming this is the source of my problem... does anyone happen to know where they should go?  I'll try to get a pic a little later...

Title: Re: AHU mk1 swap with mk3 wiring... questions/issues
Post by: vanbcguy on March 13, 2015, 11:54:40 am

Believe it or not that's actually normal on the Mk3 harness.  There's probably about a half dozen loose connectors hanging out behind the fusebox on my Mk3 and mine has an unmolested wiring harness.

There is a separate fuse/feed for instrument power on the Mk3 cluster.  There are two power feeds, one for battery voltage that's always on and activates the LCD displays for the clock/odometer, and a second one that actually powers the cluster itself when the key is on.  Sounds like you've got one but not the other.

Title: Re: AHU mk1 swap with mk3 wiring... questions/issues
Post by: Smoker on March 13, 2015, 07:58:09 pm

Quote from: vanbcguy on March 13, 2015, 11:54:40 am

There is a separate fuse/feed for instrument power on the Mk3 cluster.  There are two power feeds, one for battery voltage that's always on and activates the LCD displays for the clock/odometer, and a second one that actually powers the cluster itself when the key is on.  Sounds like you've got one but not the other.

I'd say you're exactly right.  Now to track it down...  Thanks for the info!

Title: Re: AHU mk1 swap with mk3 wiring... questions/issues
Post by: Smoker on March 14, 2015, 09:35:28 am

Bryn, I don't suppose you'd know the exact location or wire color of that power supply?  I'm scratching my head here... I do have a bentley, but I'm not good at all with wiring diagrams.

Title: Re: AHU mk1 swap with mk3 wiring... questions/issues
Post by: vanbcguy on March 14, 2015, 03:46:10 pm

Nope! It's probably in my Bentley but I'm in another country at the moment... Check out the A2Resource page though, I think it has all the CE2 color codes and things for the Mk3 cars.

Title: Re: AHU mk1 swap with mk3 wiring... questions/issues
Post by: Smoker on March 14, 2015, 03:49:16 pm

I actually got it figured out. Connector 'E' at the fuse block doesn't physically go to the cluster, but when it's listed in the Bentley as being for the cluster. Bingo.