Pilot flying C-402 encountered landing gear unsafe indication on approach.

Attributes
ACN	1650917
Time
Date	201906
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	Cessna 402/402C/B379 Businessliner/Utiliner
Flight Phase	Initial Approach
Component
Aircraft Component	Gear Extend/Retract Mechanism
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Events
Anomaly	Aircraft Equipment Problem Less Severe

Narrative:

On approach to runway xr at ZZZ; extended landing gear and got unsafe indication-right main light out. Recycled and same thing so initiated missed approach to go up and troubleshoot. Changed light bulbs per the QRH (quick reference handbook) to see if that was it but was not. Then went through the gear will not extend hydraulically procedure; got a diversion to ZZZ1. Did the nitro blow-down and still no light. [Notified ATC]. Halfway to ZZZ1; the right gear light finally illuminated. Proceeded to land at ZZZ1 without further incident-the trucks were rolled. Stopped on the runway and shut down; airport ops bussed passenger to the gate. Mx (maintenance) came to tow aircraft to the hangar and the mx staff determined that there was a loose ground wire on the strut.

Original NASA ASRS Text

Title: Pilot flying C-402 encountered landing gear unsafe indication on approach.

Narrative: On approach to RWY XR at ZZZ; extended landing gear and got unsafe indication-Right Main light out. Recycled and same thing so initiated missed approach to go up and troubleshoot. Changed light bulbs per the QRH (Quick Reference Handbook) to see if that was it but was not. Then went through the gear will not extend hydraulically procedure; got a diversion to ZZZ1. Did the Nitro blow-down and still no light. [Notified ATC]. Halfway to ZZZ1; the right gear light finally illuminated. Proceeded to land at ZZZ1 without further incident-the trucks were rolled. Stopped on the runway and shut down; Airport Ops bussed passenger to the gate. Mx (Maintenance) came to tow aircraft to the hangar and the Mx staff determined that there was a loose ground wire on the strut.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.