The message to which you are about to reply is shown first. GO TO REPLY FORM



 VIEW    REPLY TO THIS MESSAGE    PRINT   SAVE 

Bulb failure warning with LEDs 900 1994

posted by  Art Benstein on  Sat Mar 15 20:49 CST 2025
Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
last visit: Fri Oct 17 20:10 CST 2014
[RELATED]

"...what in your schematic now activates the warning light?"

That's easy. T3 is forward biased through R4 and supplies a return for the failure indicator at K. But that's the 1362367 sensor used in the late 240. I have no idea what's in your car.

"So, I ask, why is our bulb sensor design seemingly more sensitive with lower current LEDs?

Again, can't say about the 940, but your one-third two-thirds hypothesis was certainly interesting. Part number?

As to reed switch pull-in current, that depends on the number of turns and current, which for the 240's circuit I do know, is matched to the expected load. If not enough load is present, because of the LED's reduced demand, the reed switch won't close.
--
Art Benstein near Baltimore






USERNAME
Use "claim to be" below if you don't want to log in.
PASSWORD
I don't have an account. Sign me up.
CLAIM TO BE
Use only if you don't want to login (post anonymously).
ENTER CAPTCHA CODE
This is required for posting anonymously.
OPTIONS notify by email
Available only to user accounts.
SUBJECT
MODEL/YEAR
MESSAGE

DICTIONARY
LABEL(S) +
IMAGE URL *
[IMAGE LIBRARY (UPLOAD/SELECT)]

* = Field is optional.

+ = Enter space delimited labels for this post. An example entry: 240 muffler


©Jarrod Stenberg 1997-2022. All material except where indicated.


All participants agree to these terms.

Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.