Dodgy alternator

rossdg · Post by **rossdg** » Mon Jul 15, 2013 2:20 pm

Help needed bongonauts!

I put a new alternator on our 97 2.5D a couple of years ago (fleabay item). I noticed before that if the aircon is on the headlights dim when the revs drop (decelarating for instance), On sunday, with front and rear aircon on the Haydn temp/voltage alarm started beeping and displaying 10volts whenever the vehicle was doing less than 40mph. Above 40mph it was displaying 12-14v. Parked up at destination, aircon still running and alarm beeped again, showing 10v.
Possibly a coincidence, but driver side front window also stopped working on sunday, until I lifted and reinserted the switch into the door handle - then worked again, but that could be a red herring?

So thoughts:
Alternator not up to the job (was cheap)
Bad earth (I have checked all the obvious ones)
Knackered door wiring causing short of some kind

Cheers all, in eager anticipation!

Northern Bongolow · Post by **Northern Bongolow** » Mon Jul 15, 2013 6:46 pm

when ticking over and the aircon is switched on does the revs drop or do they dip for a second then pick up again.

is the replacement alternator rated at 90 amp------or less. ranger ones fit but are sometimes 80 amp rated.

maybe the aircon pump is on its way to seizing or failing.

is the thin black wire that goes from the alternator to the aircon pump intact/not damaged.

rossdg · Post by **rossdg** » Thu Jul 18, 2013 1:29 pm

....Update. The volts only drop when the fron aircon is running. Rear can be running and fan at full pelt with no drop. Pressing the auto button on the "Climate" control then causes the volts to drop, and the faster the fan, the lower the volts. Recently replaced fan resistor (transisitor - as it is a climate control version).

Running the fan only at all speeds does not seem to significantly reduce voltage.

So aircon compressor is belt driven, what electrical load is it actually demanding? Are other fans coming into play as well when the aircon is on?

Cheers all.

Bog Rat · Post by **Bog Rat** » Thu Jul 18, 2013 3:43 pm

There are cooling fans on the condenser (air con radiator) that only come on when the a/c is on

rossdg · Post by **rossdg** » Fri Jul 19, 2013 3:27 pm

To answer an earlier question regarding revs: The revs drop when the (front) ac is active, and stay dropped! What does tha mean?

Northern Bongolow · Post by **Northern Bongolow** » Fri Jul 19, 2013 7:13 pm

it may mean that the white plugged solenoid on page 2 of the following link, the picture posted by stuc------is dead, or the little vac pipes have snapped.

have a read through this lot anyway, the white plugged solenoid should lift the revs when you push the aircon on button.

http://igmaynard.co.uk/bongo/forum/view ... id#p574411

rossdg · Post by **rossdg** » Mon Jul 22, 2013 9:51 am

White plugged solenoid is working OK, i.e it clicks in and the revs rise slightly, can also see the throttle move when it clicks in. When the compressor comes on though the revs drop more and the voltage drops. Was not so bad yesterday (only dropping to 13v at tickover with AC on). It is only the front AC that drags it down.

Northern Bongolow · Post by **Northern Bongolow** » Mon Jul 22, 2013 9:20 pm

check the air con belt idler pulley bearing, they are known to seize. or even the aircon pump itself can seize or tighten.

Dodgy alternator

Dodgy alternator

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