Parasitic draw and huge voltage drop with glow plugs on GQ TD42

Hello,

I have a problem with parasitic current draw on my GQ TD42. I narrowed down the draw (it was 0,026A) to inner light and clock fuse, took it out and draw dropped to 0,009A when the car OFF.

Question - 0,009A is it ok for a Patrol, most cars have a draw of 0,006A or less as far as I know...

Second issue is connected to glow plugs - they work, car starts. I know that the previous owner did change those plugs in 2020 - so I didnt measured them separatey yet.
But what concerns me is that it works a bit atypical for me - Ignition on, glowplug light goes on for a couple seconds, but the relay goes on and off like three times in couple seconds intervals. Sends battery curent (on white green wire) when it goes on. Thing that concerns me is that when the relay goes on, voltage drops from over 12 to 8 volts, and all the lights on the dashboard go darker. Is this just a problem with battery that is not the best in the world anymore, or can it be a bigger issue?
I've checked the battery and it stil has ca. 500A when fully charged, from those 800A it had when it was new.

Regards, D.

That parasitic load will be fine mate, it is hardly registrable. Your glow plugs draw huge current, so you should expect a drop in Voltage from the battery when they are on, but what you are experiencing there suggests that your battery is well and truly on the way out.
I'd replace the battery and not worry about the static draw.

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So far so good, I managed to start the car after the night with both battery terminals on, so draw is not an issue anymore.
I figured to clean all the main terminals and what I found, that this white cable connected to +30 under electric tape was looking like this:
https://photos.app.goo.gl/8N4qL4cwVmwb74KF9
That white cable is in bad shape, full of this white/green oxydation, did fix it temporarily and it already is much better, ther is less of a voltage drop when warming up the plugs. I plan to change the whole cable in the future.