Battery or Altenator
Discussion
Hi Guys... Driving a Mondeo ST TDCI.
When we had the heavy snow, my battery light came on. I pulled over, and turned the car off, When starting the car back up, I pressed the mile reset button, and used the battery meter in the diagnostics system, the dash showing the battery voltage, it said 14.2V with lights off, and 13.7-13.8V with lights on (with no battery light when I started it back up).
Nothing for the last month, and then last night, when driving along the motorway, the light comes back on again, I've been driving around recently with Voltage showing on dash, and its been fine, I drove for about 15 miles on the motorway, and the Voltage sat at 13.3-13.3V, with the exterior lights dimming now and again.
Once again I pulled over, turned the car off, and back on, and its back to normal, with no light, and voltage readings as usual.
Any ideas what it can be?
When we had the heavy snow, my battery light came on. I pulled over, and turned the car off, When starting the car back up, I pressed the mile reset button, and used the battery meter in the diagnostics system, the dash showing the battery voltage, it said 14.2V with lights off, and 13.7-13.8V with lights on (with no battery light when I started it back up).
Nothing for the last month, and then last night, when driving along the motorway, the light comes back on again, I've been driving around recently with Voltage showing on dash, and its been fine, I drove for about 15 miles on the motorway, and the Voltage sat at 13.3-13.3V, with the exterior lights dimming now and again.
Once again I pulled over, turned the car off, and back on, and its back to normal, with no light, and voltage readings as usual.
Any ideas what it can be?
This is what I thought to start off with.
I checked the battery when I got home last night, and found its the original battery, so 5 years old, and its done 72k, so its lasted quite well I think.
Also, just thinking, if it was the alternator, surely it would have stopped charging it completely? or would it slowly be on its way out?
I checked the battery when I got home last night, and found its the original battery, so 5 years old, and its done 72k, so its lasted quite well I think.
Also, just thinking, if it was the alternator, surely it would have stopped charging it completely? or would it slowly be on its way out?
Alternators can fail intermittently and once the engine is running (if the alternator is OK) then a battery fault would have to be a pretty drastic internal short make the lights dim and the voltage drop like you are describing. Most cars don't have alternator relays and most wiring faults would not be intermittent so I'd say very likely a alternator fault.
Only other thought is that the later Fords use smart charging which can suffer from wiring issues. Take a look at the alternator, if it has one thick power wire and an a three pin multiplug (thin wires) then it's the smart charging version and might be worth getting checked by a decent sparky.
HTH
Steve H
Only other thought is that the later Fords use smart charging which can suffer from wiring issues. Take a look at the alternator, if it has one thick power wire and an a three pin multiplug (thin wires) then it's the smart charging version and might be worth getting checked by a decent sparky.
HTH
Steve H
Sounds like the start of the classic Ford battery failure. Without exception, every Ford my folks have had since the 80's, the battery has just suddenly starting playing up then died completely around the car's 5th birthday.
Some morning you'll go to start the car and it'll be totally and utterly dead.
Some morning you'll go to start the car and it'll be totally and utterly dead.
t11ner said:
Alternators can fail intermittently and once the engine is running (if the alternator is OK) then a battery fault would have to be a pretty drastic internal short make the lights dim and the voltage drop like you are describing. Most cars don't have alternator relays and most wiring faults would not be intermittent so I'd say very likely a alternator fault.
Only other thought is that the later Fords use smart charging which can suffer from wiring issues. Take a look at the alternator, if it has one thick power wire and an a three pin multiplug (thin wires) then it's the smart charging version and might be worth getting checked by a decent sparky.
HTH
Steve H
I'd second this. Ford do use a smart charge system, where the engine management system controls the output of the alternator. They are known to have a few problems with teh wiring, and possibly in teh worst case, the ECUOnly other thought is that the later Fords use smart charging which can suffer from wiring issues. Take a look at the alternator, if it has one thick power wire and an a three pin multiplug (thin wires) then it's the smart charging version and might be worth getting checked by a decent sparky.
HTH
Steve H
t11ner said:
......Only other thought is that the later Fords use smart charging which can suffer from wiring issues. Take a look at the alternator, if it has one thick power wire and an a three pin multiplug (thin wires) then it's the smart charging version and might be worth getting checked by a decent sparky.
HTH
Steve H
^^^ Wot he says. Don't buy anything until you have checked the control circuit out - the fault will probably NOT be in the alternator or the battery. A good auto-elec will have the kit to test the output and switching arrangements - it's not easy!HTH
Steve H
Superhoop said:
t11ner said:
Alternators can fail intermittently and once the engine is running (if the alternator is OK) then a battery fault would have to be a pretty drastic internal short make the lights dim and the voltage drop like you are describing. Most cars don't have alternator relays and most wiring faults would not be intermittent so I'd say very likely a alternator fault.
Only other thought is that the later Fords use smart charging which can suffer from wiring issues. Take a look at the alternator, if it has one thick power wire and an a three pin multiplug (thin wires) then it's the smart charging version and might be worth getting checked by a decent sparky.
HTH
Steve H
I'd second this. Ford do use a smart charge system, where the engine management system controls the output of the alternator. They are known to have a few problems with teh wiring, and possibly in teh worst case, the ECUOnly other thought is that the later Fords use smart charging which can suffer from wiring issues. Take a look at the alternator, if it has one thick power wire and an a three pin multiplug (thin wires) then it's the smart charging version and might be worth getting checked by a decent sparky.
HTH
Steve H
A Friend has a Mondeo and was getting intermittent LEDS lit and alarms on the dash. Ford quoted a new dash unit @ £600 ish plus fitting
He solved the problem was by removing speedo/dash unit and reseating all ribbon cables. Mondeo's us a 'Bus'.
Problem has not re-ossurrd for many months.
Worth a try and is a cheap fix.
'
He solved the problem was by removing speedo/dash unit and reseating all ribbon cables. Mondeo's us a 'Bus'.
Problem has not re-ossurrd for many months.
Worth a try and is a cheap fix.
'
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