Hearing issues on a 85 le

[tonerely]

Hey fellow Van techs!
Need advice on the following issues:

1. driving 49-50 the temp runs below the halfway mark, but when I hit highway the temp hits below red around the 1/4 mark. Should i run a coolent flush and thermostat change ?

2. heater does not heat - do I need the drain the coolant before pulling the in/out hoses the flush the heater core?

3. turn signals make the interior lights dim each signal turn.

Thanks for any feedback !

[originalkwyjibo]

Higher temps and no heat definitely suggests a clogged cooling system. If you don't know when it was done last a flush and coolant change would be a good idea. As for the lights, check voltage at the battery when it's running. It should be 13.2-14.7V with the engine running and no loads.