What type of resistor do I need?

[neverunwired@aol.com]

I'm upgrading the tail lamps on my vehicle and one set of bulbs are not
being used in the new configuration. However, these two bulbs were monitored
by the vehicle's bulb failure system.

I'd like to exchange the bulbs with two resistors (to trick the Bulb Failure
Module), but I'm not sure what kind to use.

They are 5 Watt bulbs.

Thanks
-John

 

[peterken]

"neverunwired@aol.com" <johnandhan@verizon.net> wrote in message
news:6AbQd.7071$uc.4906@trnddc01...

I'm upgrading the tail lamps on my vehicle and one set of bulbs are not
being used in the new configuration. However, these two bulbs were
monitored
by the vehicle's bulb failure system.

I'd like to exchange the bulbs with two resistors (to trick the Bulb
Failure
Module), but I'm not sure what kind to use.

They are 5 Watt bulbs.

Thanks
-John

Simplest is to "simulate" the bulbs, thus using 22-33 Ohm resistors, 5W type
On the other hand, most "fail safe systems" can detect lower currents too,
do a larger resistor *might* also do the trick
(the larger the better, since power dissipation then goes down)
A bit of experimenting might help....

 

[John Fields]

On Tue, 15 Feb 2005 00:42:42 GMT, "neverunwired@aol.com"
<johnandhan@verizon.net> wrote:

I'm upgrading the tail lamps on my vehicle and one set of bulbs are not
being used in the new configuration. However, these two bulbs were monitored
by the vehicle's bulb failure system.

I'd like to exchange the bulbs with two resistors (to trick the Bulb Failure
Module), but I'm not sure what kind to use.

They are 5 Watt bulbs.

---
If your BFM is smart enough to be able to detect tungsten, then you're
SOL unless you can substitute a load which can mimic tungsten's TCR.

If it's not, try a couple of 30 ohm 10 watt resistors.

--
John Fields

 

[rpbc]

If all else fails wire two of the proper bulbs into the circuit and hide
them somewhere. That way you won't have to worry about fooling the bulb
failure module for the bulbs will actually be in the circuit. That may be
a crude way but it will work. I do know that on some of those modules you
have to have bulbs of the same age, and sometimes of a given manufacturer,
like syvania or wagner. Sometimes the amount of current is accounted for,
other times just the current balance between the two lamp assemblies.

 

[neverunwired@aol.com]

I've tried many of the combinations suggested by everyone, but I'm afraid
I've been unable to fool the BFM with a resistor(s). I was, however, able to
wire and conceal a small 'dim' 5W bulb into the circuit...looks and works
fine. Thanks for everyone's expertise!
-John
"neverunwired@aol.com" <johnandhan@verizon.net> wrote in message
news:6AbQd.7071$uc.4906@trnddc01...

I'm upgrading the tail lamps on my vehicle and one set of bulbs are not
being used in the new configuration. However, these two bulbs were
monitored by the vehicle's bulb failure system.

I'd like to exchange the bulbs with two resistors (to trick the Bulb
Failure Module), but I'm not sure what kind to use.

They are 5 Watt bulbs.

Thanks
-John

 

[neverunwired@aol.com]

To possibly clarify something...I know that on the vehicle, the 55W fog
lights (optional), if not fitted, were replaced with a 1000 ohm (don't know
the wattage rating, etc.) resistor to override the bulb failure system. I'm
trying to apply the same concept, but I don't know the appropriately rating
of resistor needed for a 5W bulb. Obviously I need just enough current
bridged to make the module think a bulb is in place.

Don't know if that tells you how 'sensitive' the BFM is or if it makes any
difference. Not very educated in this area, just pick a little
up along the way.

And where would I locate a resistor of the appropriate rating? Thanks!
"neverunwired@aol.com" <johnandhan@verizon.net> wrote in message
news:6AbQd.7071$uc.4906@trnddc01...

I'm upgrading the tail lamps on my vehicle and one set of bulbs are not
being used in the new configuration. However, these two bulbs were
monitored by the vehicle's bulb failure system.

I'd like to exchange the bulbs with two resistors (to trick the Bulb
Failure Module), but I'm not sure what kind to use.

They are 5 Watt bulbs.

Thanks
-John

 

[Rich Webb]

On Tue, 15 Feb 2005 02:27:58 GMT, "neverunwired@aol.com"
<johnandhan@verizon.net> wrote:

To possibly clarify something...I know that on the vehicle, the 55W fog
lights (optional), if not fitted, were replaced with a 1000 ohm (don't know
the wattage rating, etc.) resistor to override the bulb failure system. I'm
trying to apply the same concept, but I don't know the appropriately rating
of resistor needed for a 5W bulb. Obviously I need just enough current
bridged to make the module think a bulb is in place.

Don't know if that tells you how 'sensitive' the BFM is or if it makes any
difference. Not very educated in this area, just pick a little
up along the way.

And where would I locate a resistor of the appropriate rating? Thanks!

If the 1000 Ohm resistors work to fool the system, then it's apparently
not terribly picky about matching the load. A 55 W lamp on a 14 V system
(running voltage) is a load of only about 3.5 Ohms. I'd guess that the
sensor is happy with pretty much any current.

If that's the case, then (with a bit of headroom) a 1000 Ohm, half Watt
should work as well here as with the foggies. Do you still have those
resistors?

Radio Shack should have some (SKU 271-1118). If 1K isn't in stock then
try the 680 (SKU 271-1117) in the same wattage.

If your local RS is one of those cutting 'way back on the components
then you can find what you need at Digikey or Jameco or Newark or Mouser
or ...

--
Rich Webb Norfolk, VA