When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
When you’re diagnosing power to the pump, make sure the engine has ran for at least 3 minutes from a cold start. It’s been awhile since I’ve looked at one for the same situation. However, if memory serves me correct, I believe there’s some logic from the climate control that doesn’t run the pump unless there’s a bit of heat in the cooling system. I also think there’s a way to get codes from the CC that doesn’t require a scan tool. If I’m wrong, feel free to chime in. I’d still bypass the pump with a barb fitting to see if there’s any change.
From memory of reading my handbook I don't think the heater kicks in till the coolant is at 35c.
Whar are the diameter of the hose inlet and outlet of that bosch replacement ? Are they the same as the original? Original has like 16mm(5/8") outlets. And does that have magnetic impleller?