Side lights and running lights gremlins

Finally got all the wiring back in the car and all setup ready to test. I hooked up the battery, everything worked perfect for about 3 minutes and then poof, drivers rear side light goes out, then passenger side rear light goes out and then the passenger rear running light and finally the passenger right sidelight. So it appears I have an electrical gremlin. When I first purchased the vehicle all those lights were out and I just assumed the bulbs were bad. Anyway after the car been restored and wiring put back in it would seem that the bulbs were not the issue after all. I replaced all bulbs with the new LED style bulbs and when I put the wiring looms back in I didn't really notice anything bad or wrong with them. I cleaned them and tidied up etc.

So does anybody know where or what is a good starting point to fault find this gremlin? From the LED being blown I'm am assuming that there is too much current possibly, so a short somewhere maybe? Any ideas would be helpful thanks.

Update: just found this guy hidden down in the black sleeve. Looks after market me thinks lol. Looks like it connects grounds from washer bottle pump, running light (+bumper light) and headlight and also the smaller inner headlight on the grille. In the bentley manual it looks like these should NOT all be connected. Where are the headlights supposed to be grounded?

Check all your grounds as they should of been separate.

Head Lights high and low are the same, side markers and washer motor are separate.

Check to verify that your Battery to frame and frame to engine grounds are good ( 0 ohms) or less than .5 Voltage drop.

Relaying your highs and low are a vast improvement, and usually makes your bulbs brighter as the current and voltage increase.

Make your new grounds to the Frame with Self Tapping sheet metal screws, and buff the paint to clear metal use ring connectors and Solder them.  After tightening the screws, spray the connection with battery corrosion paint.

For the rears I added new grounds to the tails, and side markers, tied and soldered to a large ring connector that I attached to the Bumper bolts.

Last thing was the marker light sockets, to clean them of all corrosion.

Thanks for the info Briano1234. Please see comments/response to your suggestions.

1) I'm checking grounds now after I found that beast.

2) battery is currently disconnected but did the old vinegar trick to clean up the wire for -ve like you mentioned previously. That is sitting at 0.9ohm. but think that is probably from my leads on the meter. How you check the volt drop? Battery +be to battery -ve then battery +be to chassis?

// UPDATE: 0 volt drop from connections mentioned above.

3) yeah I have a relay kit for the headlights and was going to start on that but wanted to figure out this gremlin before I start making changes so I know I didn't create a problem you know. What you think?

4) sounds like a good plan on the tails and side markers.

5) already cleaned all side marker lights.

Like I said everything worked perfectly for first three mins and then new LED bulbs started to pop and go out one by one. Like burning out.

Where are the headlights and side lights/marker lights supposed to have been grounded originally? Where that green connector for the grounds I only seem to have one brown that comes thru the cable way that's routed under the radiator. This is passenger side. On driver side the headlights both high and low and sidelights etc all have individual grounds three grounds on that side and only appears to be 1 ground on passenger side?

Briano1234, I got back to this and relayed the headlights now also. Everything works perfectly as it should except the rear taillights. Don't get me wrong, They work physically but I feel they are still pulling way to much current. I have not separated those grounds yet for the rear but the functionality is working as it should. I feel light the bulbs are almost pulling way to much load. Can almost smell the rear cluster plastic smell melting a little and they are super hot to touch from outside of light even if been on for few mins. Any ideas?

You can very easily get the wrong bulb in them, my Brother-in-law, replaced a burned out bulb in my mk1 Golf…  By the time my wife returned the lens was bubbled and cracked, the socket wasn't much better.  50 cent light bulb and 45 dollars for the lens and socket assembly.  

Make sure you have the proper wattage for the bulb.

You can even go LED for the rears, and don't have to worry about current flow.  For the turns you may need to add the resistor to them.

Bulb numbers
Cabriolet Bulb Replacement numbers | Volkswagen Owners Club Forum

Tail light
5007
5007LL Long Life

Stop light
7506
7506LL Long Life


Rear turn signal
7506
7506LL Long Life

I would look at the LED replacements, as they last longer, usually as bright, and lower current.

thanks Briano1234, I actually had LED in there to begin i used these……  https://smile.amazon.com/dp/B07TZ7HR1Z?psc=1&ref=ppx_yo2ov_dt_b_product_details  they both burnt out and took the fuse out also. So i figured it was bad LEDs or that ground issue so fixed that ground then reverted back to bulbs and now it kinda smells like the lens is being cooked by the bulbs now, so I pulled them out too. something defo isnt right…………

i used these for the bulbs……  https://smile.amazon.com/dp/B07GDC2LHP?ref=ppx_yo2ov_dt_b_product_details&th=1

now thinking to try these…… https://smile.amazon.com/AMAZENAR-2-Pack-Extremely-9-30V-DC-Replacement/dp/B07KP7VJZX/ref=sr_1_15?crid=L7XNP6JF6CQ6&keywords=5007+led+bulb+red&qid=1649281575&sprefix=5007+led+bulb+red%2Caps%2C78&sr=8-15

or these…. https://smile.amazon.com/AMAZENAR-Extremely-9-30V-DC-AK-3014-Replacement/dp/B06X6DMVY3/ref=sr_1_7?crid=L7XNP6JF6CQ6&keywords=5007+led+bulb+red&qid=1649281575&sprefix=5007+led+bulb+red%2Caps%2C78&sr=8-7

am i missing something here……… seems like any of the LEDs should be fine, including the first ones that blew. No idea whats going on. 

The LED's should of worked, but I have had new ones that were ca-ca on delivery.

You usually don't need colored bulbs, unless you are using clear tail lenses.

Also you may need a LED flasher to use is you have the turns converted to LED, or add the resistors to them as the package that I read stated:

NOTICE: The 50w 6ohm load resistor or flasher relay might be needed to prevent the hyper flash, malfunction ortrigger warning message on dashboard. AMAZENAR LED are strictly tested for sale!!! We offer fully " ONE YEAR " guaranteed for manufacturer defect.