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Sun Mar 23, 2025 10:19 am

dmmhelton wrote: I know this tread is old, but thought this might help. You can actually buy non-polarity LED BA7 bulbs that will work in original sockets. I got some on Amazon: https://www.amazon.com/dp/B0CQK2SX85?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1
Of course you'll have to use it with an LED flasher if you don't use resistors to activiate the stock flasher.
When I was hunting for them a couple years back I could only find non-polarity sensitive LED bulbs in the 1156/1157 size. Nothing as small as the BA7s. Looks like the manufacturers finally got around to squeezing the circuitry down to fit into a BA7 body.
Post back here to confirm they work properly as indicator lamps.

DesertG wrote: So if I get non polarity bulbs and have an electronic flasher, do I need to make any other mods to get oil, gen and turn signal on LED bulbs?
I see one problem if you are running a 3-prong (LED compatible) flasher relay and planning to put LEDs in all four corners as well as in the speedometer as the turn indicator lamp... insufficient load difference.
The stock turn indicator lamp arrangement depends on the sum of the corner lamps load being 20x to 40x the load of the speedometer indicator lamp. The stock bulbs are:
Turn indicator in speedometer = 2W
Corner turn signal bulb = 25W
When the turn signals are working, the load from the 2 flashing corner lamps is 50W (25W x2). When the 4-way flashers are on the 4 flashing corner lamps is 100W (25W x4). Notice how the wattage flow thru the 2W indicator lamp is so much smaller than the wattage needed to light up the corner lamps. With the turn signal lever in the L or R position, the flasher relay is powering the corner lamps, no problem. When the flasher relay pulses OFF, the 2W indicator lamp is trying to power the corner lamps thru the single 2W indicator lamp.
If you pass 2W of power thru the turn indicator lamp and then try to power two or four 25W corner lamps you could understand that 2W is far too little wattage to get the corner lamps to turn ON. The 2W of power will flow thru the corner lamps providing a ground path for the 2W bulb, allowing it to turn ON while the corner lamps appear to be OFF.
This is HOW the turn indicator lamp works with the stock turn signals.

When you replace all the corner lamps with 2.5W LED bulbs the arrangement is drastically changed. When the flasher relay pulses OFF the 2W indicator lamp is now trying to power two 2.5W bulbs (5W total). Instead of the load difference being 20x it is now closer to 2x. Will 2.5W bulbs remain ON when 1W flows thru them? Often they will glow dim. This means without any other changes, your corner lamp will now pulse BRIGHT/dim instead of ON/OFF. This is what will likely happen if you replace ALL the bulbs with LEDs.

Note: this is NOT a problem with the 4-way flashers when the ignition switch is OFF. When the ignition switch is OFF, the current flow thru the indicator lamp is reversed and it basically becomes a 5th corner lamp powered by the flasher relay. This is where you need a non-polarity LED indicator lamp to allow the bulb to light up when the current flows backwards from the turn signal flow direction.

Options to fix this so you can used LEDs in all 4 corners:
1) Add a 50W LED resistor to the L and R side turn signal circuits. Wire them as if they are a 3rd bulb on each side. This fools the turn indicator lamp. It now "sees" the stock 50W load as a low resistance path. The majority of the 2W power flowing thru the indicator lamp between flasher relay pulses will flow thru the 50W resistor as it offers the lowest resistance path to ground. So little current will flow thru the 2.5W LED corner lamps they will pulse OFF when not powered by the flasher relay. Just be sure your flasher relay can handle at least 110W of load (all 4 corners plus both 50W resistors).

2) Rewire the turn indicator lamp so it becomes a 3rd turn indicator lamp for BOTH the L and R circuits. You will need the motorcycle LED diode linked above and a 2-prong bulb holder. Ground one wire. Connect the other wire to the motorcycle diode. Connect the 2 diode input wires each to the black/green (R) and black/white (L) wire junctions. This will allow you turn just the turn indicator lamp into a constant grounded bulb which is powered when either L or R circuits are powered.
Option1 is easier. You can find the pair of 50W resistors at many FLAPS or online (Amazon or eBay). You can wire them in the trunk or at the front or rear corner lamps. Just be aware the resistors themselves will get HOT while the corner turn signal lamps are flashing. Or when you leave the car parked with 4-way flasher running. Make sure you place the resistors somewhere that will allow them to aircool.
Option2 is more elegant and makes turn signal troubleshooting easier as the indicator lamp now works more like 80% of cars on the road. Sourcing the parts needed may be harder. The 2-prong/wire bulb holder being a specialty item. WW has them but the shipping costs more than the part itself. The motorcycle diodes are easy to find on Amazon or eBay.

Nothing wrong with wanting to replace the stock turn signal bulbs with longer lasting and brighter LED bulbs. But as described above it requires some effort. For a Beetle, it is not as easy as just swap the bulbs and the flasher relay and it will all work.

FYI, if you only replace the front or rear turn signal bulbs with LEDs leaving the other end with the stock 25W incandescent bulbs (one per side)... no modifications are needed other than an LED compatible flasher relay (EP-35). The 2W vs. 25W difference (10x difference in load) is usually enough for things to work as designed.

Good luck!