should both fans come on at once?

[funinthesun]

only one seems to be cutting in at about 80 something the other is just there spectating right now.. its a 99 500.

[Cider Andy]

From you previous post about the horn, I would suspect a fusebox problem: perhaps a dirty or corroded contact in the horn/fan fuse?

[mongoose]

They should both come on at once if using the standard set up.Your car will have seperate fuses and relays,so check these as well as the connectors at the fans themselves.

Edited by mongoose on Tuesday 8th August 13:01

[harrow_chim]

Mine run off the same fuse. Check the fan connectors which will be somewhere under the radiator. They are often corroded which can lead to only one (and sometimes no) fan coming on - it did on mine until I cleaned up all the contacts.
Nick

[mongoose]

harrow_chim said:

Mine run off the same fuse........ Nick

On early cars they did Nick,however funinthesun's car is a 99 model,and so will have a seperate circuit for each.Its worth converting yours to seperate circuits(cheap and reasonably straightforward),this prevents the melted relay and burnt out fuseboard problem,which is not uncommon.