[s-cars] E-Code High Beams Stuck On

[J. Khang]

Ha, ha, yes, you are right. I meant the opposite, the forward bias direction should point towards +12V. As for the type of diode, I think any mains-rated silicon diode should do the job, maybe try a 1N400x or even just cannibalise one from an old power supply.

Jonathan

On Tuesday, 28 October 2014, 23:52, Mike Sylvester <mike at urq20v.com> wrote:
 


Not very good advice Jonathan.
I don't believe that Paul has much experience in electronics, so leaving
it to him to spec out what diode to use is like telling someone to drill
their own tooth.

In addition, adding a diode from +12 to Gnd in the forward direction
with no additional series resistance is called a blown fuse. You
shouldn't be drilling any teeth either.


Mike

> -------- Original Message --------
> Subject: Re: [s-cars] E-Code High Beams Stuck On
> From: "J. Khang" <jhlk99 at yahoo.com>
> Date: Mon, October 27, 2014 10:14 pm
> To: "s-car-list at audifans.com" <s-car-list at audifans.com>,
> "weski at verizon.net" <weski at verizon.net>
> 
> 
> Paul,
> 
> I am not sure that this is the cause or that it will work, have to try it ... the relay may be latching because the coil is slowly de-energising. Wire in a diode in parallel with the relay's coil with the diode's forward direction pointing from +12V to 0V (near the relay) and see whether that solves your problem. Your lightbulb solution could have been allowing the coil to de-energise quickly but a loose or corroded connection has removed that feature.
> 
> The contacts might, as Cody says, be welding together but I doubt that because welded contacts should not subsequently release.
> 
> You might also want to measure the voltage at the coil when you switch off the light. Maybe there is a leak from somewhere that only goes away after a little while.
> 
> Jonathan
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