what causes the heater hoses to be cold but the upper hose warm . no heat

low coolant level.must be FULL to get any heat.

I have answered this question multiple times already .. The answers I gave you are based on 44 years of experience in the auto repair business and proven fixes for this problem .. At this point I strongly suggest seeking out qualified *hands-on* help from a reputable auto repair facility as we cannot offer further assistance! https://repairpal.com/repair-shops