fuse blowing

theasylum · Post by **theasylum** » 11 Dec 2008, 15:39

t reg peugeot 806 tdi with a/c and xud9te lump. the main fuse powering the rad fans keeps blowing, simptoms inc new fuse and after starting the engine 20 sec later the 40 amp fuse blows and both fans come on all the time full tilt. if i remove the blue relay the fuse is fine. i have striped the hole lot out lookin for a squashed wire but every thing is fine

. so at the moment im driving with both fans on all the time. where do i start?

Clogzz · Post by **Clogzz** » 12 Dec 2008, 12:11

Driving with both fans on all the time, is that still with both fans at the high speed ?
Does it still do it with the air conditioning turned off ?
The aircon pressure sensor switch may be faulty.
It’s meant to spin both fans at high speed when there’s overpressure in the system.
Not sure about the 806, but on the Xantia the brown engine coolant temperature sensor wiring going open causes the fans to spin flat-out.

theasylum · Post by **theasylum** » 15 Dec 2008, 15:42

right its a long story, bought the car from a cabbie very neglected, engin overheat light came on then split second later the big red stop light, if i jerked the engine it went of for a second or two. replaced all sensors blue,green and brown, no change, suspected the bitron unit but was told they never fail and i must have a short. now the stop light does'nt come on but the large 40amp fuse keeps blowin second after the blue relay clicks. have striped it all out lookin for a traped wire but all looks fine. fuse does'nt blow if i remove the blue relay. could it be the bitron unit what side afects does it show when they fail

Clogzz · Post by **Clogzz** » 16 Dec 2008, 12:37

I suspect a stuck relay, as I’ve had.
Is the blue relay in the fan switching ?
What speed do the fans spin at without blue relay ?
Is this picture the general look ?

theasylum · Post by **theasylum** » 18 Dec 2008, 13:54

I have swapped the blue relay and tested for shorts and cant find anything. the fans run full tilt as soon as the fuse blowes does anyone know what readings i should be gettin or what the symptoms of a failed bitron unit are

theasylum · Post by **theasylum** » 18 Dec 2008, 14:03

Clogzz · Post by **Clogzz** » 19 Dec 2008, 13:07

Don’t know about that fuse box.
I expected the fan relays to be between the fans, as in the picture … does your car have that ?
The Bitron looks like it’s working normally because you do have two speeds.
Never known of Bitron faults, but they would show up as loss of fan operation or erratic speed changes.