What type of resistor do I need?

J

John or Han

Guest
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
 
"John or Han" <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.
Can you do that and still be DOT legal?
 
Yes...these bulbs are not used on the newer taillamp cluster...they are
auxilary/duplicate.
<William P.N. Smith> wrote in message
news:fqj211lnncg7iluiv1bqfp11qbopu8ntsb@4ax.com...
"John or Han" <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.

Can you do that and still be DOT legal?
 
Also...
I tried a 10K Ohm, 1/2W, 5% resistor just for kicks...didn't work either.
Would a lower Ohm rating be necessary? For 1/2W resistors they also have:
680, 560, 330, 150, and 100 Ohms.
-John

"Anthony Fremont" <spam@anywhere.com> wrote in message
news:eek:tdQd.58330$sr1.31756@fe2.texas.rr.com...
"neverunwired@aol.com" <johnandhan@verizon.net> wrote in message
news:cldQd.32971$Dc.7267@trnddc06...
Anthony,
I agree that I think the 1K Ohm resistor 'should' work. I picked up a
small
pack from Radio Shack this afternoon and tried them before hoping on
here.
They are 1K Ohm, 1/2 Watt, with 5% Tolerance. My guess is maybe the
tolerance is the issue? (If I'm not mistaken, 5% current is allowed
through?) So then maybe 10% would be more appropriate? Thanks.

5% is better accuracy than 10%. This all means that your resistors may
actually measure anywhere from 950 Ohms to 1050 Ohms. A 10% tolerance
resistor would measure out at somewhere between 900-1100 Ohms.

The 1/2W is the important issue for you so things don't get too hot.

So, didn't they work for you?
 
neverunwired@aol.com <johnandhan@verizon.net> wrote:
Also...
I tried a 10K Ohm, 1/2W, 5% resistor just for kicks...didn't work either.
Would a lower Ohm rating be necessary? For 1/2W resistors they also have:
680, 560, 330, 150, and 100 Ohms.
-John

Could it be that the detection system in your car is more sofisticated
than you think. A bulb's resistance does change as it heats up therefore
the current will change also. You might try some nichrome(sp?) resistance
wire and winding your own resistor instead. This might seem more *bulb*
like to the car.

--

Wing Wong.
Webpage: http://wing.ucc.asn.au
 
On Tue, 15 Feb 2005 03:06:53 GMT, "neverunwired@aol.com"
<johnandhan@verizon.net> wrote:

Also...
I tried a 10K Ohm, 1/2W, 5% resistor just for kicks...didn't work either.
Would a lower Ohm rating be necessary? For 1/2W resistors they also have:
680, 560, 330, 150, and 100 Ohms.
If you need to match the current draw then you'll need smaller, larger
resistors. Smaller resistance (to match the load) and a larger power
rating (so that the magic smoke doesn't get out ;-)

The original 5 W bulbs would have been something like a 40 Ohm load.
Hop back over to Radio Shack and pick up a couple of their 50 Ohm 10 W
resistors (SKU 271-133) and see if that does the trick.

--
Rich Webb Norfolk, VA
 
"neverunwired@aol.com" <johnandhan@verizon.net> wrote in message
news:hHdQd.18773$uc.3031@trnddc05...
Also...
I tried a 10K Ohm, 1/2W, 5% resistor just for kicks...didn't work
either.
Would a lower Ohm rating be necessary? For 1/2W resistors they also
have:
680, 560, 330, 150, and 100 Ohms.
A 500 Ohm resistor would dissipate about .38W, so you need to keep that
in mind. Any smaller on the resistor value and you really need to look
at a 1W resistor or larger.
 
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
"John or Han" <johnandhan@verizon.net> wrote in message
news:fsbQd.21177$uc.13297@trnddc02...
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
 
ehsjr@bellatlantic.net wrote:
As an alternative, try two 50 ohm, 10 watt
resistors in parallel. Radio Shack will
happily sell you them at 2 for $1.79.
Yeah, what Ed said. Just make sure you mount them where they have
enough airflow to cool them (don't wrap them in tape and secure them
to a wiring harness).

I'd try and see if one works, but two in parallel is a definite fix.
 
Try a lower resistance.

Also, look up "Ohm's Law." It's the fundamental principle of electrical
current and you're really handicapped by being unaware of it at this point.
 
P=E*E/R therefor R=E*E/5=13*13/5=33 ohms so use something between 33 and
40 ohms, 5watts. It might be easier to get some sockets and bulbs and use
them as the resistor making it easier to replace on burn out. 5 watts is a
lot of energy to dissipate so make sure in either case you don't melt
something or start a fire.

--

73
Hank WD5JFR
"John or Han" <johnandhan@verizon.net> wrote in message
news:fsbQd.21177$uc.13297@trnddc02...
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
 
Henry,

I appreciate your help. I'm sort of at the halfway point of understanding
simple circuits and using component parts (correctly).

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. Like I said, 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!

-John G.

P.S. Trying to keep the system clean and efficient. Would like to avoid
having the circuit extended w/ a couple of bulbs just burning w/ no real
purpose (other than keeping the BFM happy).

"Henry Kolesnik" <kolesnik@sbcglobal.net> wrote in message
news:jJbQd.47176$iC4.29834@newssvr30.news.prodigy.com...
P=E*E/R therefor R=E*E/5=13*13/5=33 ohms so use something between 33 and
40 ohms, 5watts. It might be easier to get some sockets and bulbs and use
them as the resistor making it easier to replace on burn out. 5 watts is
a lot of energy to dissipate so make sure in either case you don't melt
something or start a fire.

--

73
Hank WD5JFR
"John or Han" <johnandhan@verizon.net> wrote in message
news:fsbQd.21177$uc.13297@trnddc02...
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" <johnandhan@verizon.net> wrote in message
news:vWcQd.31157$uc.13334@trnddc03...
Henry,

I appreciate your help. I'm sort of at the halfway point of
understanding
simple circuits and using component parts (correctly).

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.
This is good information to know. It means that the high-side switch
being used in your vehicle is only looking for a path to ground to
determine if "a bulb is good". As opposed to looking for a low
resistance path to ground. The easiest thing for you to do is to try a
1K resistor and see if it works. At 13.8V (more realistic than 12V), a
1K resistor will dissipate <1/4W, but it's getting a bit close when you
allow a 10% tollerance on the resistor. You may wish to use a 1/2W to
be extra safe.

Don't know if that tells you how 'sensitive' the BFM is or if it makes
any
difference. Like I said, 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!
One paragraph and one question above. ;-)

-John G.

P.S. Trying to keep the system clean and efficient. Would like to
avoid
having the circuit extended w/ a couple of bulbs just burning w/ no
real
purpose (other than keeping the BFM happy).
 
"neverunwired@aol.com" <johnandhan@verizon.net> wrote in message
news:vWcQd.31157$uc.13334@trnddc03...
Henry,

I appreciate your help. I'm sort of at the halfway point of understanding
simple circuits and using component parts (correctly).

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.
OK, that's much easier. I had rather suspected that it would be satisfied
with much less current (more resistance) than a real bulb.

Presumably there are 12 volts across it. The required wattage (minimum) is
therefore 144/R, where R is resistance in ohms.

What I'd do is go to Radio Shack and buy some 1000-ohm 1/4-watt resistors.
Try one of them. If that doesn't work, try two in parallel. Or four in
parallel... or Radio Shack's 50-ohm 10-watt resistor. Bear in mind that a
resistor that is dissipating a high wattage gets hot.
 
Anthony,
I agree that I think the 1K Ohm resistor 'should' work. I picked up a small
pack from Radio Shack this afternoon and tried them before hoping on here.
They are 1K Ohm, 1/2 Watt, with 5% Tolerance. My guess is maybe the
tolerance is the issue? (If I'm not mistaken, 5% current is allowed
through?) So then maybe 10% would be more appropriate? Thanks.

John
"Anthony Fremont" <spam@anywhere.com> wrote in message
news:f8dQd.58216$sr1.31072@fe2.texas.rr.com...
"neverunwired@aol.com" <johnandhan@verizon.net> wrote in message
news:vWcQd.31157$uc.13334@trnddc03...
Henry,

I appreciate your help. I'm sort of at the halfway point of
understanding
simple circuits and using component parts (correctly).

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.

This is good information to know. It means that the high-side switch
being used in your vehicle is only looking for a path to ground to
determine if "a bulb is good". As opposed to looking for a low
resistance path to ground. The easiest thing for you to do is to try a
1K resistor and see if it works. At 13.8V (more realistic than 12V), a
1K resistor will dissipate <1/4W, but it's getting a bit close when you
allow a 10% tollerance on the resistor. You may wish to use a 1/2W to
be extra safe.

Don't know if that tells you how 'sensitive' the BFM is or if it makes
any
difference. Like I said, 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!

One paragraph and one question above. ;-)

-John G.

P.S. Trying to keep the system clean and efficient. Would like to
avoid
having the circuit extended w/ a couple of bulbs just burning w/ no
real
purpose (other than keeping the BFM happy).
 
"neverunwired@aol.com" <johnandhan@verizon.net> wrote in message
news:cldQd.32971$Dc.7267@trnddc06...
Anthony,
I agree that I think the 1K Ohm resistor 'should' work. I picked up a
small
pack from Radio Shack this afternoon and tried them before hoping on
here.
They are 1K Ohm, 1/2 Watt, with 5% Tolerance. My guess is maybe the
tolerance is the issue? (If I'm not mistaken, 5% current is allowed
through?) So then maybe 10% would be more appropriate? Thanks.
5% is better accuracy than 10%. This all means that your resistors may
actually measure anywhere from 950 Ohms to 1050 Ohms. A 10% tolerance
resistor would measure out at somewhere between 900-1100 Ohms.

The 1/2W is the important issue for you so things don't get too hot.

So, didn't they work for you?
 
Assuming it doesn't matter which direction the resistor is pointing...NO,
I'm afraid it didn't. What would be the next step?
-John

"Anthony Fremont" <spam@anywhere.com> wrote in message
news:eek:tdQd.58330$sr1.31756@fe2.texas.rr.com...
"neverunwired@aol.com" <johnandhan@verizon.net> wrote in message
news:cldQd.32971$Dc.7267@trnddc06...
Anthony,
I agree that I think the 1K Ohm resistor 'should' work. I picked up a
small
pack from Radio Shack this afternoon and tried them before hoping on
here.
They are 1K Ohm, 1/2 Watt, with 5% Tolerance. My guess is maybe the
tolerance is the issue? (If I'm not mistaken, 5% current is allowed
through?) So then maybe 10% would be more appropriate? Thanks.

5% is better accuracy than 10%. This all means that your resistors may
actually measure anywhere from 950 Ohms to 1050 Ohms. A 10% tolerance
resistor would measure out at somewhere between 900-1100 Ohms.

The 1/2W is the important issue for you so things don't get too hot.

So, didn't they work for you?
 
"Anthony Fremont" <spam@anywhere.com> wrote in message
news:nQeQd.58992$sr1.22845@fe2.texas.rr.com...
"neverunwired@aol.com" <johnandhan@verizon.net> wrote in message
news:hHdQd.18773$uc.3031@trnddc05...
Also...
I tried a 10K Ohm, 1/2W, 5% resistor just for kicks...didn't work
either.
Would a lower Ohm rating be necessary? For 1/2W resistors they also
have:
680, 560, 330, 150, and 100 Ohms.

A 500 Ohm resistor would dissipate about .38W, so you need to keep
that
in mind. Any smaller on the resistor value and you really need to
look
at a 1W resistor or larger.
0r two 1000 ohm half watt resistors in parallel to give 500 ohms. Or
two 220 ohm half watt resistors in series to give 440 ohms, 1 watt.

Etc., etc., etc., to add up to however much wattage and resistance that
you need. Just don't run the half watt resistor at a half watt, because
the heat tends to burn them up over a long time.
 
"Henry Kolesnik" <kolesnik@sbcglobal.net> wrote in message
news:jJbQd.47176$iC4.29834@newssvr30.news.prodigy.com...
P=E*E/R therefor R=E*E/5=13*13/5=33 ohms so use something between 33
and
40 ohms, 5watts. It might be easier to get some sockets and bulbs and
use
them as the resistor making it easier to replace on burn out. 5 watts
is a
lot of energy to dissipate so make sure in either case you don't melt
something or start a fire.
I agree with the idea of using light blubs for the load. However the
high currents in the light bulb should not be necessary for a controller
to detect it as an okay filament. Try using some resistors that are
higher, like maybe 1000 ohms.


--

73
Hank WD5JFR
"John or Han" <johnandhan@verizon.net> wrote in message
news:fsbQd.21177$uc.13297@trnddc02...
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 wrote:
Also...
I tried a 10K Ohm, 1/2W, 5% resistor just for kicks...didn't work
either. Would a lower Ohm rating be necessary? For 1/2W resistors
they also have: 680, 560, 330, 150, and 100 Ohms.
If you bought a packet of 1000 Ohm resistors, try two in parallel
to give you 500 Ohms and if that doesn't work try three (333 Ohms)
and four (250 Ohms). Twist the wires together to make sure that
every resistor is passing current.

It would be useful to put the original bulb across the ends of the
wires to verify that the module is working and can still tell that
the filament not broken.


--
Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial
WIMBORNE http://www.wessex-astro-society.freeserve.co.uk/ Wessex
Dorset UK Astro Society's Web pages, Info, Meeting Dates, Sites & Maps
Change 'news' to 'sewn' in my Reply address to avoid my spam filter.
 

Welcome to EDABoard.com

Sponsor

Back
Top