Haltech and A341e

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Sorry, I'm not familiar with the Haltech loom. I made my own to fit my elite 2500. Re-pinned a Wolf V550 loom to Haltech.
I've found Haltech stuff to be pretty good, but hey they are just humans.
I agree you should read close to 0V on DPO6 when the ign. is on. The reason why I say close to zero volts, will depend on how hard the driver switches to ground with the load you have on it, and if its just a normal relay then it should be pretty much 0V. If the load was say 10Ohms, then you might read a couple of volts as the driver can only push 1A to supply.
However there are other conditions that must be met for you to see a switched Gnd @ A25 (DPO6) and switch the relay on. Most 12V relays will operate with about 8Volts on them and will hold down to about 6V
The only thing that should be connected to A25, (DPO6) is the ECR relay coil (pin 85) and the other side of it (86) connects to battery. The relay coil should measure approx 120 - 200Ohm between 85 & 86.
1) You must also have a Gnd on A10 & A11.
2) You must have ign. switched +12V on A13.
If the above checks out, I would disconnect the ECR relay (85) from A25 DPO6 and connect a low wattage test lamp (something that drags less than 1A) to A25 and the other side of the test lamp to battery. Switch the ignition on (ie. power on A13) the test lamp should light. Measure the voltage at A25 (should be your Gnd). If that works then you got something else connected to DPO6 loading to battery +ve.
That is DPO6 doesn't have enough balls to drive to ground cos of the load is pulling it to battery.
If you were close by, I drop round and give ya a hand, but SA is a little way a way.
Good luck. Hope this is of help.
Yes i have checked all the possible things. Spent some time with a Haltech tech this morning as well but still no joy. Not too concerned with the voltage at the grey and red when switched off but still can't find why i have constant power as S1. Am sending the ecu to Haltech for testing just for piece of mind before i totally remove the loom from the car and open it up further. Unfortunately all the electrics are mounted in the left kick panel of a 37 Chev and is very awkward to check things. Have open a lot of the loom already and found nothing