I have been chasing some running issues with my car and was checking the grounds.
Positions #5 (shielding for reference sensor) & #28 are both connected to the same ground point MP VIII (engine block), but #28 is 15k ohms and #5 is .03. I have checked the other year wiring diagrams and they show the same thing. I am pondering if I should jumper to a good ground or not. The wire and connector looks good on the visible end. This ground is just for the DME, so if the diagram is correct, this is important.
Does anyone have a good harness out they could check? Thanks.
DME ground #28
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Tom
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The manual's schematic shows pin 28 connected to ground, so that should be that. In the DME board-level schematic, it seems to be a dedicated ground reference for an analog to digital converter, but I'd be surprised if it isn't tied to other ground planes inside. It's definitely connected to other ground wires in the harness. But I do have my old harness handy (after installing the Kroon) so will confirm that and report back.Cruise98 wrote: Sat Feb 28, 2026 9:33 am I have been chasing some running issues with my car and was checking the grounds.
Positions #5 (shielding for reference sensor) & #28 are both connected to the same ground point MP VIII (engine block), but #28 is 15k ohms and #5 is .03. I have checked the other year wiring diagrams and they show the same thing. I am pondering if I should jumper to a good ground or not. The wire and connector looks good on the visible end. This ground is just for the DME, so if the diagram is correct, this is important.
Does anyone have a good harness out they could check? Thanks.
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Tom
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Just tested and confirmed:
DME pin 28 connects inside the harness to the smaller brown bellhousing ground wire, as does DME pin 5. So with the connector pulled off the DME, you should see continuity (close to 0 ohms) between engine ground and DME pin 28, and likewise continuity between DME pins 5 and 28
DME 16, 17, and 19 all connect inside the harness to the bigger brown bellhousing ground wire. With the harness out of the car, there is no internal connection between the two bellhousing ground wires. So you will not see continuity between 16, 17, and 19 on the one hand and 5 and 28 on the other hand. With the harness in the car, the two bellhousing ground wires are connected together at the bellhousing, so if you just remove the DME connector in the footwell with the harness installed in the car, you should see continuity (close to 0 ohms) between any and all of 5, 16, 17, 19, and 28.
Seems like the problem must be between the 35-pin connector and the internal connection point connecting 5 and 28 to the small bellhousing wire. If it were after than, you'd see the same thing on pin 5 (which I understand you do not). My guess is the issue is right in the connector. I'd pull back the connector's cover and look for frayed wires on pin 28. That would be an easy win.
DME pin 28 connects inside the harness to the smaller brown bellhousing ground wire, as does DME pin 5. So with the connector pulled off the DME, you should see continuity (close to 0 ohms) between engine ground and DME pin 28, and likewise continuity between DME pins 5 and 28
DME 16, 17, and 19 all connect inside the harness to the bigger brown bellhousing ground wire. With the harness out of the car, there is no internal connection between the two bellhousing ground wires. So you will not see continuity between 16, 17, and 19 on the one hand and 5 and 28 on the other hand. With the harness in the car, the two bellhousing ground wires are connected together at the bellhousing, so if you just remove the DME connector in the footwell with the harness installed in the car, you should see continuity (close to 0 ohms) between any and all of 5, 16, 17, 19, and 28.
Seems like the problem must be between the 35-pin connector and the internal connection point connecting 5 and 28 to the small bellhousing wire. If it were after than, you'd see the same thing on pin 5 (which I understand you do not). My guess is the issue is right in the connector. I'd pull back the connector's cover and look for frayed wires on pin 28. That would be an easy win.
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Tom
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Finding the faults in old harness is 99% of the battle, so things could be worse! The worst are intermittent hiccups 'somewhere' in the harness...Cruise98 wrote: Sat Feb 28, 2026 11:53 am Thanks for confirming. I am seeing continuity at all of the positions except 28. Time to repair that.
Old wiring harnesses!#%&!!!