Hi, I'm having a issue at the moment whenever it's cold normally and u start the car, the instrument cluster looses power briefly and resets itself including the time and everything. I have been sujested that it could be a bad earth but does anyone know where the earth for this is, Haynes manual just gives a general area of where it is which would be hard to give without needlessly taking stuff off

The instrument display is the victim, not the cause. No need to go rummaging below the fascia or taking the instrument pod off.
Low battery power causes this, as when cranking the voltage drop goes below that necessary for the display and clock, so it effectively sees a battery disconnect.

In most cases a new battery fixes this.

The main earth cable from battery to body and gearbox tends to corrode. First check the connections where this cable attaches to battery, gearbox and car body. If possible, check for continuity along it, while flexing it. They have been known to break internally.
If you have jump leads, pop one from battery negative to a good engine point. If display now ok, earth lead is suspect.

:yeahthat:

Been a few these last few weeks. Guess it's the first time its been cold for a couple of years.

Right, the battery was new provably a year ago, I will have a look at these connections, do you know where the main earth connects to?

daniels471 said:

Right, the battery was new provably a year ago, I will have a look at these connections, do you know where the main earth connects to?

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Trace the heavy cable connected to the battery negative. it should go to a bolt on th chassis and then to the engine block or gearbox.

Robert G8RPI.

Right,after some further investigation ,i tried using a jump lead from neg battery terminal to the engine ,and with that in place ,i dont get the issue ,so from that i can assume its a fault on that cable somewhere although i couldn't see any obvious corrosion or anything ,whats the best way to go about a repair or anything ?

daniels471 said:

Right,after some further investigation ,i tried using a jump lead from neg battery terminal to the engine ,and with that in place ,i dont get the issue ,so from that i can assume its a fault on that cable somewhere although i couldn't see any obvious corrosion or anything ,whats the best way to go about a repair or anything ?

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Hi, Depends on your skill set and tools. If you are good with tools, buy a length of cable and do it yourself. Otherwise you could buy a new cable assembly from Fiat or a generic pre-made cable with lugs that you can fit to the existing battery clamp and ground point.
There is the option of taking the old one off, cleaning it all up, squeezing or soldering the crimps, but this is unlikely to produce a reliable long term fix as the rot has literally already set in.

Robert G8RPI.

if i was to do this myself , would i add an additional wire just to the chassis to provide the extra ground required or would you replace the whole lot ?

Hi,
All new, a cable from battery to chassis and one from chassis to engine.

Robert G8RPI.

The cables corrode inside, so replacement is the only proper fix.
A genuine cable will have a terminal mid-way for the body connection, but an aftermarket cable will not. Opening the outer sheath to crimp a terminal is a job for someone who knows what they are doing.
A genuine cable from Fiat will probably be expensive.

However, easy option.
Measure the length from battery to first connection, I think it goes to the body first.
Then measure from there to the other end.
Now pop along to Halfords, or any local car accessory shop and see if they've got two cables of those lengths, one with a negative battery terminal and the other with an eyelet of the correct size at each end.

https://www.autoelectricsupplies.co.uk/product_list/31
http://www.vehicle-wiring-products.eu/section.php/93/1/pre-made-battery-leads

As a quick test you can unbolt a starter lead from a breakers

It's long enough to bolt from the battery negative to the plate on the gearbox that holds the gear selector cables.

Only problem is its the wrong colour

The main earth lead goes from the battery to a stud on chassis just in front of the battery tray then on under the tray and onto a stud under the clutch slave cylinder.

The fault of corrosion internally inside the cable does not generaly affect the Pandas any more. Fiat now seal the ends of the cable with heatshrink. Both mine 06 and 05 have this upgraded cable.


Where it use to go was the last joint and would not pass enough current to crank the engine.


Which doesn't "fit cold normally and u start the car, the instrument cluster looses power briefly and resets "

The instrument cluster does no have its own earth and is connected to the same earth as the body computer via the wiring harness.


Disable the car from fireing up(pull the fuel pump fuse). Put a volt meter across the battery and measure as you turn the engine over would take the guess work out.

OP has already isolated the issue to the earth lead, see post #6

Robert G8RPI.

g8rpi said:

OP has already isolated the issue to the earth lead, see post #6

Robert G8RPI.

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Yes I seen it.

Adding an extra earth can be just a sticking plaster. I have done this as a temporary fix. Yes it starts a little quicker giving it less time to drop below the critical level.

Half the cranking volts and you double the cranking amps.

The way to go is to measure on top battery. Thus elimination any cables.

Yes if the volts don't drop too much sort out an earth problem.

Cranking for 8 seconds and it shouldn't fall below 9 volts.

koalar said:

Yes I seen it.

Adding an extra earth can be just a sticking plaster. I have done this as a temporary fix. Yes it starts a little quicker giving it less time to drop below the critical level.

Half the cranking volts and you double the cranking amps.

The way to go is to measure on top battery. Thus elimination any cables.

Yes if the volts don't drop too much sort out an earth problem.

Cranking for 8 seconds and it shouldn't fall below 9 volts.

Click to expand...

Hi,
The voltage drop in a good earth cable is so low, halving it by addding one in parallel will make no difference to the available voltage.
If you halve the the voltage to the starter you do not double the current. You would have to double the current to get the same power, but that is a design issue. Supply half the rated voltage will reduce the current draw. It will not be half the rated current, it's not that simple. Reducing the voltage to a DC motor reduces it speed, the current depends on the torque. Assuming the mechanical load is high the current will hardly change with reduced voltage but the speed will drop significantly so the supplied power is less.
Anyhow that is well off topic, the OP has a fairly new battery and a jump lead removed the symptoms so I'm ver confident that a new cable will fix the problem. If you wanted to tell for sure which it was you would have to record the current, battery voltage and the voltage drop across the battery ground lead. I have the kit to do that but very few owners and most garages dont.

Robert G8RPI.

g8rpi said:

Hi,
The voltage drop in a good earth cable is so low, halving it by addding one in parallel will make no difference to the available voltage.
If you halve the the voltage to the starter you do not double the current. You would have to double the current to get the same power, but that is a design issue. Supply half the rated voltage will reduce the current draw. It will not be half the rated current, it's not that simple. Reducing the voltage to a DC motor reduces it speed, the current depends on the torque. Assuming the mechanical load is high the current will hardly change with reduced voltage but the speed will drop significantly so the supplied power is less.
Anyhow that is well off topic, the OP has a fairly new battery and a jump lead removed the symptoms so I'm ver confident that a new cable will fix the problem. If you wanted to tell for sure which it was you would have to record the current, battery voltage and the voltage drop across the battery ground lead. I have the kit to do that but very few owners and most garages dont.

Robert G8RPI.

Click to expand...

Yes the voltage drop is low on a good cable. Just over 1 volt. However adding another halfs it. Thats why on my marginal battery it was a quick fix untill the battery was changed. Also turns ovet slightly quicker and start slightly quicker

The way to go is to measure across the battery while cranking thus eliminating any cables. Standard volt meter will work just fine. No special equipment needed. If it was me I would measure, not guess. As I said if it tests fine move on to the next step. After all its cost nothing and very little time.

Yes the battery is nearly new. Still doesn't mean its okay. Also doesn't mean its getting fully charged.

The dash is reseting because the volts are droppin too low. Adding a jump lead from earth to the engine still has to go through the same "faulty" chassis earth point just in front of the battery but it is helping with the starter motor.

Not unless the original poster is jumping to somewhere different

koalar said:

Yes the voltage drop is low on a good cable. Just over 1 volt. However adding another halfs it. Thats why on my marginal battery it was a quick fix untill the battery was changed. Also turns ovet slightly quicker and start slightly quicker

The way to go is to measure across the battery while cranking thus eliminating any cables. Standard volt meter will work just fine. No special equipment needed. If it was me I would measure, not guess. As I said if it tests fine move on to the next step. After all its cost nothing and very little time.

Yes the battery is nearly new. Still doesn't mean its okay. Also doesn't mean its getting fully charged.

The dash is reseting because the volts are droppin too low. Adding a jump lead from earth to the engine still has to go through the same "faulty" chassis earth point just in front of the battery but it is helping with the starter motor.

Not unless the original poster is jumping to somewhere different

Click to expand...

OP jumped from battery negative to engine (post #6 ) bypassing the original earth lead for the high starter current but leaving it in place for the relatively low current for chassis mounted equipment. I don't think the OP has a voltmeter. The chances of difference of 0.5V drop on a good negative overcoming symptoms of a faulty battery are extremely low.
It's a subtle point but the dash is not resetting because the battery voltage is low but because the voltage across the earth lead is too high causing the effective voltage to be too low.


Robert G8RPI.