(Newbie) golf mk5 1.9 TDI : losing all electric systems when left in the sun...

[evon]

Hi all, newbie here.

I have a golf mk5 1.9 TDI 2004 with a very particular issue :

• Car stays parked in hot sun for 2-3 hours
  
  • when started, car will run fine for 10-20mns
  • then electric systems go down one by one
    
    • A/C (only fan was active at the time, not A/C)
    • turn signals / stop lights
    • sometimes car radio (not always)
    • power windows
    • all dashboard light and screen
    
    
  • then finally the engine stalls... fun when you're on the highway...
  
  
• If I try to start again : no power at all (dashboard lights and screen off) : nothing
• If I wait one minute: dash lights come back, but the car can't start : starter stuttering (clack-clack-clack) like with a dead / weak battery
• once I leave the car off for a few minutes (2-3), the car will start again and run for 5-10 mns
• then the cycle starts again...

This seems to only happen only when the car has been sitting in the sun...

What I've tried so far:

• I've checked as much as I could of the electric wiring, fixed a few messes the previous owner(s) did
• checked and replaced any fuse that seemed in bad shape (found some that look slightly corroded, and one blown, with copper wire to "repair" it... )
• checked light connectors and repaired / replaced when needed (one had a pin burnt : replaced the connector and soldered new wire with clean pin)

I've done extensive research but couldn't find anything about it...

Anyone has any idea ? going crazy trying to find the fault here !

Much thanks!

Dan