LED tail lights

[(unknown)]

My son as fitted LED tail lights to his Renault Clio (1.2 2001)When they are switched on and the engine is started they go off!! With the engine running they can be switched on and off no problem. The original bulb type work fine. I have even wired them in sharing the same supply and earth, the bulb type remain lit whilst the LEDs go off and will not come back on until the switch is re operated.

I have replaced the battery on the car but this as made no difference, again as soon as the car is started the LEDs go off.

Any suggestions would be much appreciated.

Many Thanks Tiggsy

Not really an automotive forum here. Resectioned.

[veewee77]

Depending on how they are wired, it could be that the voltage is too low when the car is just on and not started. LEDs require a minimum voltage to light up. If there are too many in series, and the voltage is too low, they will not light. Then when the car is started, the alternator raises the voltage high enough to light the LEDs.

Doug

[finnsawyer]

It sounds to me like you must have some type of solid state (safety?) circuitry before the LEDs.  When the car starter turns over the voltage to the tail lights drops.  This causes the solid state circuitry to shut off the lights.  It then requires recycling (i.e. hitting the switch) to turn the lights back on.  One solution would be the addition of a second battery, not affected by the starter.  Not a very satisfactory solution, though.  

[finnsawyer]

Or maybe it's in the switch itself.

[wooferhound]

You could put the old bulbs back in

[disaray1]

My thoughts exactly Woof.

[Opera House]

A 100 ohm resistor in parallel with the lamps might be enough current to hold the electronic circuit on.  A lot of effort, but you are going for a look.  Starting a vehicle normally drops the voltage a couple volts.  LEDs are usually stacked in series and act like a zener, below a certain voltage the lamp no longer conducts. Don't understand the need for a hold circuit like this, but having owned a Pugeot understand the French are apt to do anything.

[Cloaked User]

I wasn't going to say anything, but since you brought it up, I had a Renault for several years long ago. It was a tough and efficient little car, and comfortable too, but boy was it weird! I had lots of electrical misadventures with it, including a small fire. You had to get parts from the nearest Jeep dealer then. That was long before anyone thought of LED taillights, so I have no advice that hasn't already been suggested.

That car got 32 mpg on the highway, 25 years ago. I drove it hard for about 90,000 miles at a net cost of under 13 cents per mile. Purchase price, interest, taxes, license, insurance, fuel, tires, repairs, duct tape, everything. My present work truck costs just about 13 cents per mile for fuel.

[Cloaked User]

Oops, dadgummed typo! My present wheels cost me about 23 cents for a mile's worth of fuel. Yikes!

[elvin1949]

I get 50 miles to the hamburger on my bike.

later

Elvin