I would give him as much as you can get into him for now (a common amount seems to be 3-6 mL) & then count/measure/weigh his food tonight - if you have some other method you can keep him warm with (turning the house temp up, a space heater), I would try turning the lamp off for tonight & use the other method, just to make sure it really is that. You could also try scattering some kibble in bed with him, he may be willing to eat it as long as he doesn't have to come out in the light to get it. If it doesn't look like he's eaten much or at all in the morning again, I'd syringe-feed him again, then see if you can get the other heating equipment tomorrow & get it switched out soon. Sounds like he's hungry & willing to eat, so that's good!
~*~*~ Kelsey ~*~*~
RIP my sweet Lily ~ 6/12/08 - 1/20/12