hmm.
reminds me of my most recent job on my 480Turbo.
between the hinges of the hatchwindow the wire run , packed in "rubber " from the car body, through the outside of the car, to the window frame.
the outside rubber was gone hard by the environement and the 16 years of age. But, it looked OK.
My wiper didn't find its way home no more... by accident i found out that if i touched this 15 cm of cable bundle between body and frame... it did.
I took away all the rotten rubber and found a car electricians nightmare: all cables it selves were gone hard ( the plastic insulation that is) and cracked all over.. short cutting all over like a thunder cloud.
I guess the UV radiation, heat and air polution did its work there.
I spend a relaxed afternoon soldering, renewing and insulating ( the plastic that closes the window frame went out well, it was a hot day)
to a satisfiing result.
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depart from this:
try to fix a bulb of the volvo specs between the ground you found and the brake switched current..
-There is a chance the ground is no good one. (measure resistance(Multi m. in Ohm) between the ground piont at the left rear light and the guessed ground wire. )
-and there is a chance the cables inside the previous bundle rubber are "burned spagetti" like mine. (be aware of water leaks, work well overthought)
- other facts could be that the resistance of the bulb acc. to specs will kill the 8,3 volts that are over the twio leads in rest. (attention : is this also with ignition off ? don't do it than, it will drain your battery.!)
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one last thing :
I had only two loose cables here both with the white connectorinsulation caps.. I can't explain from here why you have 3. Some with nothing on em ?????
