Blinker weirdness

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.


Dec 2, 2018
Hey Mudders, can I tap into your experience and wiring expertise for a moment?

‘76 FJ40 mostly stock. Restomod style.
I have converted every bulb to LED except the headlights which are H4 with a relay harness. I am extremely happy with the improved lighting, especially on the dash and cluster.

There is an issue that I need to sort out though. When its raining the turn signal display in the guage cluster misbehaves. The indicators that is selected illuminates appropriately, but the bulb that should be off also lights up and flashes dimly.

My guess is that cracked wires or an exposed harness plug is “bleeding” voltage through the rain wet insulation to the other circuit and since LEDs require such low voltage to illuminate, I am seeing it on the dash. The wrong side exterior turn signals don’t appear to be illuminating when wet, just the dash. Although I haven’t pulled off the lease cover and looked close for dim illumination.
This phenomenon happens with both right and left turns. It resolves once dry.

My plan is, on a dry day, to have the blinker on, and sequentially wet down different areas of the rig until the issue appears.

Have you ever experienced this? And can you point me toward a connection or wear point that might be the likely culprit in this case if intermittent flasher missbehavior?
I had an issue with snow accumulating on the vampire splices under the rear wheel well. The splice was for the tow hitch wiring. I had to tuck all the splices into the rock guards for the tail lights. Snow was shorting out the running lights and blowing the fuse.
My turn signal ground wasn't great, disassembly wasn't going well with rust, so I added a ground wire and got my lights and indicators operating as expected.
Well, I would have said ground issues but you said everything was converted to LED. I would STILL either run separate ground wires to each light, or make darn sure you have good metal to metal contact for the light grounds.

One ground that a lot of people forget is the gauge cluster ground. A nicely painted dash/gauge cluster will not ground well. Make a ground jumper with a bullet connector in the middle that goes from the frame of the gauge cluster to a bolt on the body. When you need to remove the gauge cluster, just unplug the bullet connector.
My LED conversation involved buying replacement bulbs for all locations, but still using existing sockets and wiring. The only re-wiring I did was for the headlamps and H4 bulbs. I made solid grounds there. I have had my dash apart. No new paint, but I will make up the ground you describe. I will verify clean solid grounds at all 4 corners for lighting & report back.

Users who are viewing this thread

Top Bottom