If the space is too tight for you to get in there yourself, you can use an inspection camera instead. No need to look for a power outlet, since it runs on batteries. Just get at it!
From Amazon
Bosch Professional 12V System Thermal Camera GTC 400 C (12V Battery + Charger, W/App function, Temperature Range: -10 degree C to +400 degree C, Resolution: 160 x 120px, in L-Boxx)
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