Backup lights coming on briefly, then going off

[5.0gray90']

The backup lights in my truck come on when i put it in reverse, but then go off after a second. anybody have an idea?

 

[Earl43P]

Depends on what year truck you are talking about and which transmission it has.

Your 90 would have a reverse switch on the left side of a manual transmission. They are usually red in color and have a two wire connector. An automatic trans would use the Neutral Safety Switch for the reverse lights. It may need adjusted.

A 2001 would use the same type of reverse switch on the manual transmission. The automatic would use what is now called the DTRS (digital transmission range sensor), mounted to the input spline of the shifter linkage, left side of transmission. They are adjustable by loosening the two or three 10mm mount bolts.

 

[5.0gray90']

its on a 2001 4x4 auto.