Civic EG

so last night driving in peak hour traffic, i switch on my parks lights and my temp gauge rises almost to overheating position, i switch off parks and the temp drops to normal?

now i goolgled this and only came across two threads- one on honda-tech but cant open it and another but its a mustang having this problem- i read that and they say its got to do with low voltage (can be because i need a new battery) but what else can it be.


also it didnt happen again after i flushed the cooling system (just thought there was a air bubbles).

PLease Help lol.

might try a different battery? last resort is new alt.

Most Likely a bad ground