Alternator warning light coming on dash
new alternator fitted
new cable fitted from alternator to fuse board
still warning light comes on
Any ideas?
Is it actually charging? Stick a voltmeter across the batteries and see what that tells you. You should be seeing a little over 25V with ignition off, something like 28V with engine running (you’ll need to see at least 27.6V for the battery to charge), ideally between 28.4V and 29V.
yes over 28v
In that case I think the vehicle electronics are misreporting a fault when there isn’t one. No surprises there, given it’s a Daf…
Problem is, you could poke around and swap out components until the cows come home and still not find the actual problem.
yes thats what im worried about
hoping now its a chafed wire somewhere
take off the multi pin plug on the back of the alternator. with the key off you should have a positive with 24v nothing and a 2nd wire with a negative (this is a signal to the dash).
turn the key on but dont start. the wire that had nothing should now have 24v. if you only have 1 wire with 24v with ign on then it may be that the 24v to the alternator is missing. this normally breaks about 6inches down the loom. this normally puts the warning on the dash and still charges the battery.
is the signal getting to the VIC ecu in the cab ??Aas that is what will extinguish the warning on the DIP
Zimbowreker:
take off the multi pin plug on the back of the alternator. with the key off you should have a positive with 24v nothing and a 2nd wire with a negative (this is a signal to the dash).
turn the key on but dont start. the wire that had nothing should now have 24v. if you only have 1 wire with 24v with ign on then it may be that the 24v to the alternator is missing. this normally breaks about 6inches down the loom. this normally puts the warning on the dash and still charges the battery.
i have ruled this out by replacing the all wire from alterntor plug to fuse board to make sure there are no breakages
norb:
is the signal getting to the VIC ecu in the cab ??Aas that is what will extinguish the warning on the DIP
some one said this yesterday to me might be vic ecu
do you know how i would test this to see if im getting signal?
and would this stop the battery charging?
sheep1:
norb:
is the signal getting to the VIC ecu in the cab ??Aas that is what will extinguish the warning on the DIPsome one said this yesterday to me might be vic ecu
do you know how i would test this to see if im getting signal?
and would this stop the battery charging?
Can’t help with the first bits, but if you are getting 28V+ at the battery terminals then it will be charging (even if the vehicle electronics think otherwise).
sheep1:
norb:
is the signal getting to the VIC ecu in the cab ??Aas that is what will extinguish the warning on the DIPsome one said this yesterday to me might be vic ecu
do you know how i would test this to see if im getting signal?
and would this stop the battery charging?
I honestly don’t know the wire number off the top of my head…so I can’t help there …I’m guessing the truck is EURO3 so it my be an idea to check the otherside of the socket on the bulkhead to make sure it isn’t corroded…Have seen issues there
yes euro 3
the plugs on the bulk head have been cleaned up and a few replaced
will it be a wire off the vic going to the bulkhead that will be no good?
sheep1:
yes euro 3
the plugs on the bulk head have been cleaned up and a few replaced
will it be a wire off the vic going to the bulkhead that will be no good?
so you have definitely checked the back of the pins on the bulkhead…
I’ll try and find the wire number tomorrow if I get time
cheers
got the auto electrician coming at lunch time
i had the alternator tested by a company on friday afternoon the guy told me to link the signal cable to the live next to it
then it would charge and put the light out on dashboard
Did your spark turn up■■? Sorry I never got time to check diagrams ,mega busy just now
Check alternator feed wire to starter “star” distribution peg.
Common fault on all trucks as “manufacturers” cheapskate on feed wire.Any wire carrying 150 amp at full load deserves more than some cheap tagged on ring.
Thats why alternators fail.They pump themselves up to max output and the bloody cheap wiring then overheats, the voltage rises and either arcs out the brushes or burns out the diodes or regulator.
If the alternator runs at full output it has to be able to shunt it to the batteries.
replaced the battery so far so good
he said he did the wiring last week to vic ecu
so if the battery does not solve it he said it will be the ecu unit itself
sheep1:
replaced the battery so far so good
he said he did the wiring last week to vic ecu
so if the battery does not solve it he said it will be the ecu unit itself
You can get 1 from a scrap vehicle ,it will have to be the same part number /version …The relevant info is on the ecu…Then if you take the vehicle to a dealer ,the will be able to change the chassis number on the vic
ok thanks
sheep1:
replaced the battery so far so good
he said he did the wiring last week to vic ecu
so if the battery does not solve it he said it will be the ecu unit itself
Which ECU? The alternator runs at full power ,the regulator senses battery voltage and if battery voltage is high the power transistor turns off the slip ring power to reduce alternator output,if battery voltage is low it turns on the transistor for a longer period so that alternator current rises.
The alternator/battery is a self regulating unit.