fabia strange electrics

[carmadrob]

hi, trying to sort my mums fabia 1.4 mpi, manual, petrol, heres the symptoms, all warning lights on dash randomly come on, car still drives spot on, turn car off and back on then its ok but airbag light on, stereo looses all stations, battery light comes on when i turn key so not that dmf wire issue, battery connections good, alternator signal wire seems ok, wires under battery ok and tight, also noticed when it lights up like a xmas tree the indicators dont flash in dash but still work outside as normal, seems like a faulty earth but checked earth from battery to inner wing and that seems ok, where is the other earth strap on the fabia, sorry for such a long problem, cheers

[poiuytre111]

Just because the red light comes on before you start is not a guarantee that you do not have the alternator wire issue - suggest you check it as it is such a common cause of trouble.

[carmadrob]

thanks for reply, is the wire somewere on the gearbox ? also is the alternator a 3 stage unit , when i hold revs at 1500 rpm and turn fan on full with rear screen dimister revs drop down to 1000 rpmm cheers

[TMB]

How old is the battery?

[poiuytre111]

The alternator wire in question runs underneath the battery area or slightky forward of there and there is a plug/socket in that area that should be obvious.

[carmadrob]

not sure on age of battery to be honest but no problem starting car, just seems like power to all dash and stereo cuts out which in turn throws up all the lights when it gets power back if you know what i mean, like flicking the power off then back on , i first looked into cluster fault but that wouldnt affect the stereo, unless the main loom power supply as a loose connection somewere, not sure if main power supply is from ecu or direct from battery, cheers

[Breezy_Pete]

Measure voltage across battery terminals before and after starting engine.

Check tightness and clean-ness of connections while you're there. Edit: you say you've done that, sorry.

Edited 29 November, 2015 by Wino

[carmadrob]

cheers will do first thing in the morning

[carmadrob]

right update, battery ok, went to start car and it run for a couple of seconds then dies, says error on dash, disconected battery for a while and when i connected back up away she went, no problems, ive tested alternator charge on battery and got 14.5v with engine running and no electrics running in car but volts suddenly drop to 2 v- 8v then back up to 14.5v, so i checked direct to alternator and same, volts up and down, that cant be normal so i assume alternator is at fault, what do you think? cheers

[carmadrob]

bump anyone

[vindaloo]

hi, trying to sort my mums fabia 1.4 mpi, manual, petrol, heres the symptoms, all warning lights on dash randomly come on, car still drives spot on, turn car off and back on then its ok but airbag light on, stereo looses all stations, battery light comes on when i turn key so not that dmf wire issue, battery connections good, alternator signal wire seems ok, wires under battery ok and tight, also noticed when it lights up like a xmas tree the indicators dont flash in dash but still work outside as normal, seems like a faulty earth but checked earth from battery to inner wing and that seems ok, where is the other earth strap on the fabia, sorry for such a long problem, cheers

 

Earths.... 1 or 2 more are around the NS front turret, facing the gearbox/engine. Someone posted a piccie not long ago. Should be easily found on a 1.4. On other cars the airbox occludes it.

 

J.

[carmadrob]

cheers will check earths but cant see how that affects voltage from alternator then again i suppose alternator is earthed, just seems weird when i connect battery back up everything goes back to normal, for a while anyway lol

[poiuytre111]

If I understand correctly, you are seeing reasonable voltages that occasionally dip by over 2 volts. Either the charge current is cutting out altogether (14.3v to 12.4v) or you have a serious short dragging the voltage down. Given the relative costs, I would be looking into changing the alternator. Easy enough to diy change.

[fabdavrav]

Is there a voltage regulator in the alternator near the bushes?....................could be the cause............

[carmadrob]

right fitted a new alternator, checked earths, one from battery to top of strut, other from gearbox to inner wing area, both good, checked spark plugs to see if they had any cracks, did this to see if they could be arking and spiking current, they look good. checked all fuses, ecu is dry but undid plugs and checked pins and they look fine. started car up and runs fine but checked voltage on battery and direct from alternator, idle im getting 14.5 v on both, but every now and then for a split secong voltage jumps to 6v, 8v, 14.5v , took car out and after 10mins warning lights come on again, rev counter drops, oil light comes on and bleeps, indicators stop flashing in cluster but work outside, steering wheel light comes on, if i disconnect battery for 5mins its ok for a few more miles, anything ive missed lol

[TMB]

Have you checked the fuse links on top of the battery? They can develop hairline cracks which are hard to see but can cause intermittent connection havoc.

 

These I mean...

 

Edited 4 December, 2015 by TMB

[carmadrob]

cheers, when you say airline cracks are they where they bolt on or cable side, they look good and tight but i will try anything at the moment, not sure if i have a pet mouse behind dash lol

[TMB]

cheers, when you say airline cracks are they where they bolt on or cable side, they look good and tight but i will try anything at the moment, not sure if i have a pet mouse behind dash lol

 

The middle area of the fuse links sometimes crack. Like this but it's not always this obvious....

 

Edited 4 December, 2015 by TMB

[TMB]

^ The one to the left looks cracked in that pic as well.

[sepulchrave]

Replace the brush pack on the alternator.

[TMB]

Replace the brush pack on the alternator.

 

He's fitted a new alternator. Do keep up.

[sepulchrave]

He's fitted a new alternator. Do keep up.

 

Oh dear, missed it.  :peek:

[carmadrob]

cheers for that, will check in the morning

[carmadrob]

well checked for cracks but found none,  tried a diagnostics with a delhi ds150e but that wont even connect to car, just says check cable and check car is obd compliant, passes port and interface check, but thats another story lol, plugged a cheap reader into car, connected no problem, found no faults but reader only reads engine, you would think it would of picked up a fault because i have to take battery earth off for a minute to reset immobiliser else car wont start,

[TMB]

You're going to have to get it properly scanned with VCDS.