Technical Electrical problem

[Bigt75]

Hi I recently purchased a 2009 fiat panda 1.2 petrol . I wondered if anyone can help. While driving the abs light, handbrake light come on and the speedo and fuel gauge drop to zero. It only happens for about 2 seconds and they work fine again there is no loss in power but it does reset the clock time . Just wanted to know if anyone knows what it could be .
Thanks Tony

 

[koalar]

"reset the clock time"

You don't need to look at the other symptoms until this is fixed, there probably related

The body computer (BSI) has seen less than 6.5V

That the potential difference, between the ground and supply, the fault can be in the supply or ground

the supply can be 14.2V but if the ground is at plus 8V the difference is 6.2V and the clocks will reset


The fact it comes back points more to it being something loose or dirty


Battery
Battery connectors/ terminals
Chassis ground
Block ground

Visual inspection, followed by a Voltage drop test under load is the obvious first step


Very similar to this one with the gauges dropping

2009 Panda Flashing ABS & Steering when indicating | FIAT Panda (Mk3)

Realise this is a pretty common thing, I have checked all the power/earth leads, battery has also been replaced. When indicating, the ABS then Steering Symbol come on one after the other, then go out again. These stay off unless indicating...so I know it is an issue either inside the instrument...

www.fiatforum.com

 

[Bigt75]

Are there any diagrams for the earth leads ground ect

 

[koalar]

Sure

Have you got a multimeter

Voltage drop test under load is the way to go

Being intermittent you will have to gently wiggle the wires also

Id start thith the battery terminal and chassis rail/leg



The BSI is earthed to the chassis via a connector on the passengers door A post, But is the chassis could already be hit so check the rail fist

 

[Bigt75]

I have a multimeter I will check the earths too thank you for your help

 

[koalar]

Clean the top of the lead battery negative terminal to shiny metal one probe here

File a bit of the top of stud on the chassis rail to shiny metal, other probe here

Multimeter to volts, if it's not auto ranging pick the first one over 15V

Turn the rear window heater on, blowers on full

Should measure under 0.2V, there's a bit of leeway

Shouldn't alter if you wiggle the cable

Switch everything off

Clean a spot on the cam cover, the lugs where the airbox bolts to are a good spot, one probe here the other on the battery negative, get someone to crank the car and observe the matter reading reading, again under 0.2V good

 

[Bigt75]

So not the battery and not the earth's. Will have to be booked in garage on Monday