Poss Battery/Alternator issue

[RAINMAKER]

Right straight to the point..

Had to take the v6 out tonight put the usual on lights, heater and heated seats for the wife it was at this point i noticed the battery light (very dim) but there..now i turned off my heated seat and the light stayed on then turned off the passenger one and off goes the light. Turned mine back on and light still out, then back off, turned on the passenger seat on the light comes on.. i then did the same again without the headlights on and i had the same..
It seems the battery light comes on when i switch on the passenger heated seat.The battery has recently been changed along with the alternator for the last MOT..
Looking for some direction to go on this any help please.....

[v6 steve]

wouldn't the heated seat pull more current than the lights sound like the alternator might need some tlc, does you alternator cooling fan work ?

[RAINMAKER]

Id only just started the car from stone cold, cooling fan is fine, alternator is brand new not recon..
The light only comes on when you switch on the passenger heated seat steve..

[cornishtaz]

Check the wiring from the alternator to battery as this is a common fault, cabling isn't up to the job when heavy current is required

[RAINMAKER]

Baz.. where does the cabling normally route..

[cornishtaz]

the thick red wire runs along the back of the block to the battery the earth is obtained by the mounting bolts of the alternator you've then got the main earth from battery to chassis

[RAINMAKER]

ok ta, Ill be testing the cross pole volts tomorrow and then the wiring..
thing is it only does it when the passenger heated seat is put on..

[cornishtaz]

you could always carry out a resistance reading of the 2 heater mats in the seats then use this equation to work out the current drawn from each seat

I=V/R current drawn = 12V/resistance reading

you might find that the passengers seat has a higher resistance so causing your problem.

What does your volt gauge read during the above situation

[v6 steve]

bad earth on the seat ?

[RAINMAKER]

passenger seat gets very hot compared to the drivers...

[cornishtaz]

could be your drivers heater mat is knackered or you've got a short on the passengers one

[RAINMAKER]

i know they tend to have a prob where the wiring goes around the hindge, i will check this also tomorrow..

[Stupink]

could also be that you have a vauxhall??? lol.
check the batt volts, you may find it is actually still charging, wouldnt be the first time, my old tubby was like that, but then that did only have an el useless 70amp alt. so it was asking a lot of it.