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Brand new battery drained! "dome fuse 7.5A"


berg

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Long story short...

 

Bought a brand new calcium deep cycle battery from halfords in December

 

Car has been perfect, no issues

 

Last week i removed a mines ecu, and plugged in a standard ecu and wired in a HKS FCD

 

Drove it to MOT and then drove it home fine

 

Car has sat for 5 days and now is flat as a pancake, wouldn't even read on battery tester, fully charged booster only just managed to start the car

 

Only thing thats changed is the new ecu and fcd, and also it was sat the 5 days with the clocks and top dash panel off as i wired in the speed delimit wire and never put the dash back together until today.

 

Any ideas what could cause it so suddenly?

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Will do that in the morning

 

Never had a problem until now and the only changes are the new ecu

 

Fitted defi gauges around 3 weeks ago but again no issues up until this point, and i cant see 4 gauges pulling that much power to save memory

 

Will pull fuses and hopefully get to the bottom of it

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It didnt take long to find the culprit

 

7.5A fuse labelled "dome", when this is pulled the amp drops to 0.04 where it should be

 

Strangely when pushing this fuse back in i hear my defi gauges make a noise, the defi gauge is wired into the oem clock plug so im not sure how that fuse is linking with my gauges somehow??

 

From my understanding the clock wiring is on the same circuit as the cig lighter, when the cig lighter is pulled the current draw doesnt change, thats the circuit my gauges are on

 

Yet when i pull the dome fuse the gauges are making a calibrating noise when the fuse is plugged back in

 

Confused.com

Edited by berg (see edit history)
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I would say they are not on the same circuit as a cigar fuse would be about a 15 - 20A fuse also I think the cigar power is lost when the ignition switch is off and the clock obviously should stay powered up.

The only thing I can think of that links the cigar and clock is instrument illumination.

I will check wiring diagram/ colours etc later for you. What colour wire did you connect the gauges to? what about the earth/negative connection? did this get connected to the clock wiring as well? or separate earth?

 

it sounds as if you have connected the gauges to the permanent live of the clock?

 

hope you get it sorted. I will help if you need it but it will have to later today.

 

regards chris.

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The 4 wires for the gauge are wired to the 4 wires of the clock harness as the clock has the same features as the gauge

 

1 x ignition live

1 x illumination so they light up only with headlights

1 x earth

1 x permanant live (this is only to store the setting in the gauges, obv stores the time on the clock)

 

They are definately wired correctly, everything works as it should and they do go off with ignition as they should, the permanant live connection to 1 wire is only to store the peak, warnings etc that i set on them

 

I have unplugged the gauges and my readings are showing 0.04 amps so they are definately drawing too much power when off, why im not sure yet lol

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Im not too sure, i hope not

 

Defi manual says max power consumption with 7 gauges is 0.1A ign and 0.2 amps with all illuminated

 

Fact i have only 4 and im using 0.3 amps with everything off, something isnt right lol

 

Control unit unplugged for the time being

 

Ive triple checked the wiring and its 100% correct, everything works as it should with regards to switching on/off/illuminating with headlights etc

 

Maybe ill try a different earth point to rule that out, cant see that having an impact though

Edited by berg (see edit history)
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