I have a 2001 Monaco LE 38' that when the furnace starts the 12 volt interior lights dim momentarily. According to the Monaco tech the latching relay in the left front basement electrical compartment was the culprit. I changed this and still have the problem. I'm connected to a 50 amp service. New batteries were installed 9 months ago because they were bad, so I know this isn't an issue.
I had to replace the blower motor in the furnace last week so I know that can't be the problem. I'm looking for a location to check the voltage drop other than the blower motor.
Any suggestions would be helpful.