Technical body computer trickery or something else?


New member
Jan 8, 2016
I have an x250 2007 model. Are the symptoms below screaming body computer or am I missing something obvious? If so is this a simple plug and play job after purchase from Fiat, have multiecuscan 3.1 also. Can a body computer be picked up 2nd hand, or is it an expensive visit to Fiat dealership?

I have Polished all earth straps to chassis fit good connection. Also have done all of the usual water in ingress work on the scuttle etc. Also as a side question, I have a slipping clutch, any ideas of a rough replacement cost, at independent not main dealer. Many thanks in advance.

The main beams have refused to engage intermittently and now it seems more permanently, the switch stalk is OK as gives signal to dashboard and blue light comes on and if I bypass the body computer and jump an earth from the wiring on the out side of the body computer it works fine. When I multimetered the bridge it showed as 12.7v and I expected it to drop to 0 when the earth was active but only dropped to 5 or 6v. I am guessing this means the voltage to the relay was insufficient to energise it hence no lights.
I had to do the same on the windscreen washer circuit recently adding a manual switch after the body comp to provide an earth; however when pulling the washer on the stalk it still activates the 5 wipe programme without the wash!
The wipers also have an annoying habit of failing to come on on one of the settings and have to click a few of the speed settings to get them to engage, or may be on fit a while and stop only starting on selecting of a different speed. Feels like they are powered by Windows software with the amount of lag time between input and response.
I also have all glow plugs failing to get energised despite entire writing getting continuity checked and plugs and relay replaced.


New member
Apr 30, 2014
Adriatic island
The body computer has a list price of 520 euro. To me that seems quite expensive.
Before make such a donation to the Fiat dealership I would dig a little deeper in the wiring. You already found at least one output that didn't switch to ground, so maybe all other faults originate from the same phenomenon. The body computer certainly has more than one ground contact, if the output ground has a high resistance that could be the source of all problems.
Even if a crimped connector looks clean it can still make a poor contact to the wire.

I had other electrical issues last year, caused by insects (mud wasps) who built a nest under the relay board in the main fuse box, destroying several contacts that looked O/K from the top.


New member
Jul 21, 2011
id be checking every earth i could find and clean and reconnect even add another from the engine to the chassis
Cheers adam