gwgeep

Just noticed that my back-up lights do not work. Checked the bulbs-OK; checked the voltage from the engine compartment power box to the Manual Lever Safety Switch also known as the Neutral Safety Switch and that is okay; I get no voltage at the back-up lights. So, I know that voltage is getting to the NSS but it does not appear to be getting out to the back-up lights. My NSS has power in and then out to backup lights and it not a separate brake light sender. So, the question is: Do these NSS go bad such that voltage is not sent out to the back-up lights? Is this a possibility? My p/u always starts fine; no direct issues with tranny problems as a result of a bad NSS; BUT, is there a possibility that voltage out to the B/U Lights could be the only problem within the NSS? All other rear lights operate just fine; just only white BU. It is 25 years old and would this type of issue be an internal mechanical failure or internal ground/electrical failure?

Steve83

The MLPS is a multi-circuit switch; one circuit CAN fail, leaving the others functioning. This caption contains info on testing it:


(phone app link)

This site has most of the wiring diagrams:
http://www.bbbind.com/free_tsb.html
It requires an e-mail, but it doesn't have to be real or yours. When you see the WIRING DIAGRAMS button, click it.

gwgeep

Okay, found a brittle wire near a connector leading to the B/U lights. It was between the MLPS and the b/u lights. Must have dislodged it when putting things back together during the fuel tank installation. All fixed and good to go...