Glow plugs....

Hello! I haven't posted in a while, as my car has been running fantastic! I wanted to post this morning, as I am running into a small (maybe non) issue with my 99.5 ALH Golf TDI 5 speed. When i bought the car the glow plug harness was all busted up and i had glow plug codes. I put 4 new plugs in, and fabricated a harness using primary wire, Bullet connectors, and everything has been great! However, if i remember right, I may have Wired the two circuits together, to create basically one glow plug circuit. I feel with the super cold temps we have had, my plugs aren't quite working the way they should.... I plan on taking the harness i made apart and disconnecting the two circuits and see if i throw a code (presently i have none). I don't remember WHY i wired them together, maybe possibly i threw a low resistance code when i first did it? I don't know. They work, but like this morning, 28 degrees... Cycle key, let light go out, count to 5, turn key off, turn back on within a few seconds, let light go out, count to 5, start... crank... crank... crank... crank.... crank... fire
maybe 6-10 seconds of cranking.... this is my first TDI, but not my first diesel, and in my previous experience, my GM and Ford diesels started a little easier, but still a temperamental @#$!#^% in the winter. Thoughts? Advice?

Thank you all!

Seems like a loot of trouble. Just check the resistance of each plug. Should be about .6 Ohms, I fink.

So often people go straight to blaming the glow system for hard starts, when usually it is not the case unless there is some sort of DTC stored. Normally I would say if you have no glow related DTC stored, your problem is not with the glow system. However your home made harness (not sure why you would do this) and maybe non-approved plugs would give me pause.

Loss of fuel prime from a leaking injection pump can also cause a long crank time in the cold.

How old is the battery and is it a 94R?
Put an overnight charge on it and see if it doesn't fire right up.
The GP circuit is just 2 feeds, so what you have seems fine to me. You easily check the resistance on each plug and the V reading at the 4 connects.

I give mine a few seconds after the GP light goes out also.
The off/on and wait is only if it gets below 20 (F) and a 2nd wait a few seconds.
Don't know if the 99.5 has 2 GP fuses in the box over the battery.
Check for a good connection with them also.
For testing if you pull the coolant temp sensor the plugs will have power much longer.

How long does the GP light stay on?

What's the cranking RPMs? You need good speed (I would want to see at least 200 rpm, though spec says minimum of 150).

Check for air in the fuel lines.

I just started mine while cold in 9°F weather. The glow plug cycling light stayed on for a while but as soon as it went out I cranked and it started almost immediately. It starts up great around 20° but tonight it had a little shudder to smooth out. I’ve never had a car start this good in the cold. My coolant plugs aren’t even intact, the covers all broke off the plugs. My point is it can start great!
Check for moisture on injection pump too

As was mentioned earlier, check out the starter.
I replaced mine last month and it is amazing how slow the old starter was turning the engine over. I installed an acdelco reman. unit from rockauto. Looks like all Bosch parts were used on the rebuild.