OBC Question...

Scania · 20 Mar 2009 at 13:20

I'm pretty sure I already know the answer to this.....

One of my tail lamps failed on the way home last night, so I swapped it with a spare that I carry.

Trouble is, the bulb is a 24v item (for a truck) not 12v and the OBC still reports "Tail Lamp Failure"

Guessing - I assume that this is due to different resistance between the bulbs?

I'll try to get a 12v bulb on the way home although tbh there seems to be little if any difference between the brightness of the two.

Siliconslave · 20 Mar 2009 at 13:26

yer, i'd imagine its just not showing the right resistance in the circuit so throwing the OBC for a loop... the 12v might well fix it

InvaderGIR · 20 Mar 2009 at 13:27

Voltage is different to wattage, so brightness doesn't surprise me.

Sounds like a 12v is needed though.

Scania · 20 Mar 2009 at 13:31

InvaderGIR said:
Voltage is different to wattage, so brightness doesn't surprise me.

Sounds like a 12v is needed though.

Weird - I've noticed doing the reverse - putting a 12V bulb in my Scania - makes the bulb extremely bright (until it pops!

)

I'll get a correct bulb & see if that makes it happy.

InvaderGIR · 20 Mar 2009 at 13:32

R420LA6X2/4MNA said:
Weird - I've noticed doing the reverse - putting a 12V bulb in my Scania - makes the bulb extremely bright (until it pops! )

I'll get a correct bulb & see if that makes it happy.

'cause it's overvolting.

Django x2 · 20 Mar 2009 at 13:34

Yes, its all to do with resistance. 12v or nothing. Less or more equals bulb warning lamp

Jez · 20 Mar 2009 at 13:36

For the same brightness (wattage, and in turn current) a 24v bulb will have a completely different resistance to a 12v one.

Come on lads, think back to school, V=IR

So yeah, replace the bulb, this bulb should be dimmer too.

Scania · 20 Mar 2009 at 13:46

Jez said:
this bulb should be dimmer too.

I'll check the brightness in the dark later....