NO CHARGING STILL

[V8Dom]

hi

i have had an ignition switch problem...replaced today

but still have no temp guage reading and no charging!! engine runs

temp guage if i ground guage shoots up so think its a sender fault.

ign on no battery light. start engine 12v at battery and on guage. so not charging

the bulb itsself is ok on the warning light and there is a supply of 12v in the green wire, but no earth in the yellow/brown. traced wire to alternator... so alternator is not giving an earth signal with ign on..

the other small wire attached to the alternator is a green wire.. this has no voltage at it? which i presume it is supposed to as wiring diagram suggests green at alternator connects direct to main alt cable'+'

does anyone know where the green wire goes to and is it a perminant live?? if so can i just joint it to the '+' terminal of the alternator??

Also seems starnge the volt meter and alternator and ign switch have all faulted at the same time???? read threds previously about updating the wiring, but want at least to get it working first before cutting main wire..

thanks dom

[MarkWebb]

Green wire is the sense wire. It should be connected to the wiring loom at a point where voltage drop has occurred so in an ordinary car this would usually be where the big pos wire feeding the fuse panel enters the fuse panel. This then controls the alternator voltage regulator to give @14.2 volts at that point. An Ultima loom has multiple pos wires supplying the various high current stuff attached to the pos term on the battery. The wiring diag shows this wire connected directly to the charge terminal which is perm live. As long as your charging wire is man enough then that is not too much of a problem. It needs yo be live to make alternator work! The fact that the ign bulb wire is not at 0 volts with engine stopped (making the bulb come on) and going to battery volts with engine running so stopping current from flowing through bulb. Makes me think that the regulator on the alternator is suspect. However get battery voltage on green wire first. If still no good have alternator tested. Sorry to be long winded.

Edited by MarkWebb on Tuesday 14th August 20:08

[V8Dom]

hi mark.. i presume the green wire at the alternator has to be switched rather than perminant live otherwise regulator would be live all the time... as you say diagram shows it live all the time???

I ll run a temp wire in to alternator and check.. thanks dom

[MarkWebb]

Yes live all the time no prob. I would also recommend using relays to reduce current through ign switch.

Edited by MarkWebb on Tuesday 14th August 21:36

[Steve_D]

Green wire in the Ultima loom is ignition switched live.
The wiring diagram for 'Dry sump (not LS7)' shows three pins
Brown/yellow on one
Green on another
Brown on the third

Brown is permanant +12V.

Steve

[MarkWebb]

Not what my diag shows but not that it matters either way.

[V8Dom]

steve have you got dry sump wiring diagram??


And where does the green wire go to from the alternator,, i can see any greens at fuse box?

Dom

[MarkWebb]

I think what Steve is saying is that Green wires in the Ultima loom dictate that they are ignition switched lives. However the drawing shows the sense wire(green) connected directly to the brown +ve charging wire, The brown/yellow to the ign bulb. The sense wire needs to get battery voltage switched or unswitched does not matter.