Glow plug power issues

Help in need of some input/help/direction. I have read numerous posts of glow plug issues and this is where I'm at.
Having trouble tracking down the cause of the glow plug codes and check engine light on my '04 Jetta Tdi with the BEW engine, 5 speed manual. A little history: Started to rebuild the old girl about 2 yrs ago as I miss driving her. New fenders, rockers, timing belt, filters, fluids and complete body restoration. It now runs, sounds and looks all original. It was having an small glow plug issue pre-restore, at that time for cyl. 2 glow plug but I never pursued at the time. Now restoration is complete and it is giving the check engine and all 4 glow plug codes. Thought it was strange to have all 4 GP codes so decided to check GP's with ohm meter and they all checked well within spec at .7 . When pulling the GP harness off most of the boots broke so purchased a new harness and spliced the wire under the cover near the original connector, so the splice would be more out of the elements. Cleaned the grounds from the engine to body while there. Fired up the VCDS and still had all 4 GP codes. Cleared all the codes and re-ran the VCDS. Still all 4 codes. After researching the issue seems the GP relay was next in line as the problem. Installed another GP relay and VCDS still giving all 4 GP codes. Stumped. Ohmed the female connector pins to each GP boot in the harness, all OK. Checked each boot for power after unplugging the coolant, nothing, no power to any of the boots. Checked all connections at the battery and all fuses on top of the battery, all is good at 12.8 v. Disconnected the harness plug again and tested the pins for supplying power to the GP from the GP relay, no voltage there. Checked for power at the GP relay, the big blade near the bottom that should have constant power and had 12.8 v at that point. Should add the glow plug light on dash lights up and goes out as it should.
Thoughts running through my brain, is ECU giving signal to GP relay? How could that be checked? What are the chances that 4 wires from GP relay to connector under the cover behind the air box being bad at the same time? ( Don't want to strip all the wire covering off the harnesses until everything else has been checked out). Is there a bad ground I'm missing somewhere? I did clean up the ground near the ECU. The GP relay has 9 pins, top row is power to GP's, center 2 pins of middle row?, bottom row left pin? center blade pin 12v constant power, right pin?
Any Ideas?

What was the code# ??

This is the VCDS log for the last scan. Hope it's posted correctly.

Address 01: Engine Labels: 038-906-016-BEW.lbl
Control Module Part Number: 038 997 016 R HW: 028 101 114 6
Component and/or Version: R4 1,9L EDC G000SG 0282
Software Coding: 0150031
Work Shop Code: WSC 95884 999 13913
VCID: 2D51602CB73719273C-5142
5 Faults Found:

16502 - Engine Coolant Temp. Sensor (G62)
P0118 - 000 - Signal too High
Freeze Frame:
RPM: 0 /min
Torque: 186.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 12.16 V
Bin. Bits: 00001100
Temperature: 3.6°C
Temperature: 4.5°C

17055 - Cylinder 1 Glow Plug Circuit (Q10)
P0671 - 000 - Electrical Fault
Freeze Frame:
RPM: 0 /min
Torque: 186.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 12.16 V
Bin. Bits: 00001100
Temperature: 3.6°C
Bin. Bits: 00110000

17056 - Cylinder 2 Glow Plug Circuit (Q11)
P0672 - 000 - Electrical Fault
Freeze Frame:
RPM: 0 /min
Torque: 186.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 12.16 V
Bin. Bits: 00001100
Temperature: 3.6°C
Bin. Bits: 00110000

17057 - Cylinder 3 Glow Plug Circuit (Q12)
P0673 - 000 - Electrical Fault
Freeze Frame:
RPM: 0 /min
Torque: 186.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 12.16 V
Bin. Bits: 00001100
Temperature: 3.6°C
Bin. Bits: 00110000

17058 - Cylinder 4 Glow Plug Circuit (Q13)
P0674 - 000 - Electrical Fault
Freeze Frame:
RPM: 0 /min
Torque: 186.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 12.16 V
Bin. Bits: 00001100
Temperature: 3.6°C
Bin. Bits: 00110000


Readiness: 1 4 1 1 1

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Address 01: DTCs cleared

Where did you get the harness? Any chance you can check the new harness for continuity from the bridge to where you spliced it?

Check for battery voltage on both sides of each of the fuses on top of the battery. There is a little confusion but I think the second fuse from the drivers fender is a glow plug fuse, not the green ones the larger metal ones. Make sure they all have battery voltage on each end.

Guessing the CTS code is cause you disconnected it.
Sounds like you've went about the troubleshooting in a fairly logical and complete fashion.
12v battery.
Slow blow fuse good (check contacts as well)
B+ at relay.
relay connects to ECU for instructions, GPs for power.
So either you've missed something, you spliced the wrong wires or the ECU plug is loose or has bad connects.
I don't think, but am not sure if the GP 5v 7v ECU reflash is germane.

Thanks guys. I'm going to be working at the issue again on the weekend and let you know the results. Although it says I have been only recently registered, I was a member of this forum many years ago, never posted but read many posts if a problem arose with my Tdi's . Had an 02 AHL and now a 04 BEW since 2009, but changed service providers and forgot my password so had to re-registar.

Fixed many issues with both by reading posts on here and this is an excellent place for good information. Still reading through posts from the thread that Wingnut started with concerning glow plug issues/trouble shooting, but only 1/4 through it at this time.

Tdijarhead, the continuity from the splice to the GP harness is good. I tested it from the harness connection in the raceway behind the air box, this is where I did the offset splice for the GP harness. Bought the harness from Brian Harrison of Roseland . He is only 2hr drive from me. There is power on both sides of all fuses, but I did not remove the connections to check for corrosion, add to the to do list. Thanks for the info.

BobnOH, Yes the CTS was disconnected to give more time to check the power at the GP harness boot. There was none at any of the 4 boots.

"Slow blow fuse good (check contacts as well)"?? Not sure if I know where this is but I did not clean the contacts of the fuses in the power box above the battery, add to the to do list.

"B+ at relay".?? again not sure what you mean by this, but there is power at the relay constantly at the large blade on the bottom row of the relay connector plug.

"relay connects to ECU for instructions", GPs for power. I fully understand this, and now looking to that as the root of the problem. I will check things out more on the weekend. What I cannot figure out is which wire at the relay plug is the signal wire and can it be tested for the signal.

Again, thanks for your input, much appreciated that you have taken the time to respond. I am desperately trying NOT to cut these harness apart to trace wires and I do not have access to any wiring diagrams.

Slow blow fuse contacts, simply pull it out and look at (or clean) the contacts in the holder.
B+ is simply shorthand for battery voltage (12).

You 04 should be the same as my old 03. At least the GP relay is the same at ID-Parts.

The GP relay gets power from fuse 163. Its 50 amp, on top of the battery.
Goes to pin 2 of the relay, red heavy wire.

The relay does connect to the ECU, pin 9. It's blue / black color. Pin 10 on the relay.
Not sure if it's power or signal.

The relay grounds at the center of the firewall. I would measure the voltage from the back of the socket the relay plugs into to the center post of the battery negative post.
With the key on (GP light on) I would not want to see more then a few tenths of a volt.
If more, clean the ground at the center of the firewall and the one under the battery.

Also check for power to pin 6 (yellow black) of the relay.
If none, check fuse 34, 10 amp in the inside fuse box.

Hope this helps.

Well finally had time to do some more trouble shooting on this elusive glow plug issue. I again want to thank all who contributed their suggestions and knowledge. As I have said many times in the past " you can't fix stupid". BobnOH after trying a few more things and having no luck, I revisited the splice location. BobnOH replied a suggestion that rung in my head for a few hours, "you spliced the wrong wires". How could that be, I splice the wires from the GP harness into the up facing part of the connector. Well as it has it, where I spliced the wire to the connector was ( as it should be ) the same colors from the GP harness, but those colors were from the GP relay and not from the GP harness itself.

When I pealed the tape I put on after I did the GP harness splice, I tested the continuity of the 4 cut bare wire ends to the corresponding GP relay pins and BANG, I had CONTINUITY. I had in fact cut and spliced the wires on the wrong side of the connector.

Now back to why I cut and spliced the wrong end of the connector. I am a plumber by trade, therefor this is the only defense I can come up with why I did what I did. In my mind the "up" facing part of the connector should have housed the GP harness wires because it was facing up and leading from the GP harness (lower), but those wires were actually the GP relay wires from above under the cowl. The connectors other end, facing "down" actually had the wires from the GP harness.

Moral, water runs downhill, electricity can run any direction. I thought the connector facing up was logically where the GP harness lead too since the GP harness was downstream of the connector, how wrong I was.

All is good now, thanks again.

Glad you got it fixed & posted the resolution.
It may help others down the line.