93 LS 400 relay clicking on cold start

[Herm]

Greetings.

93 LS400 160 k miles (california emissions). On cold start hear relay clicking about once per second with slight light dimming in sync with relay clicks. Lasts about 1 to 3 minutes, then no more clicks. I can hear when sitting in drivers seat, sounds like from engine compartment but I can't tell for sure- hard to localize source. Has anyone run into this ? Appreciate any ideas.

Thanks - Herm