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dontlikewelding

New Member

• Jan 27, 2015

• #1

I have a rather annoying overnight battery drain, I have disconnected the battery overnight and it has held charge fine- the alternator is providing a good 14v+ charge.

With the ignition off the alternator makes a buzzing noise which stops when you disconnect the rev gauge, reattach the rev gauge wire on the alternator and the buzzing starts again, with the ignition off the rev gauge wire has 7.2v coming from the loom down to the alternator (disconnect the wire from the alternator and the battery does NOT drain) originally I believed this to be a regulator problem on the alternator however after replacing the regulator on the alternator the problem persists.

So if I disconnect the rev gauge wire on the alternator the battery does not drain and this wire has 7.2v constantly being fed to it.

HELP!

 

Saint.V8

Dyed-in-the-wool 100% RR Junkie

Full Member

• Jan 27, 2015

• #2

Short in the instrument binnacle maybe??

Check the binnacle for signs of corrosion or tracking....the binnacle has a feed from the alternator to the warning light for 'no alternator charge' so there could be tracking across from this area to the rev gauge connection causing a minor short and giving you the voltage feedback....

Worth a look!

 

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dontlikewelding

New Member

• Jan 27, 2015

• #3

Would that not cause the rev gauge to fail? It works perfectly when plugged in !

 

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dontlikewelding

New Member

• Jan 27, 2015

• #4

right, nothing obviously on the back of the panel- HOWEVER, I suspect the EAS is at fault.

If you pull out the 15 amp fuse in the glove box for the suspension then this kills the 7.5v which is traveling down the rev gauge wire to the alternator, put the fuse back in again and the 7.5 returns to the rev guage wire.

So I guess it's the EAS which is killing the battery- where's the best place to start?

 

Saint.V8

Dyed-in-the-wool 100% RR Junkie

Full Member

• Jan 27, 2015

• #5

The EAS needs an 'Engine Running' signal, so I can only assume it gets this from a tap-off from the gauge feed considering the issue you are having.

Is it possible to unplug the EAS ECU and then see if you still get this voltage even with the fuse still plugged in but ECU out??

If it goes, then it could be an internal fault to the EAS ECU...if it is still there, then it could be a case of wire chasing to see if there is a chaffed spot causing issues!

 

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dontlikewelding

New Member

• Jan 27, 2015

• #6

I know where the ECU is, so will try that tonight, the only other option is the EAS relay i guess?

 

Datatek

Well-Known Member

• Jan 27, 2015

• #7

Could be a diode gone in the alternator, you could try an external 1N5401 diode in the alternator wire with the diode connected arrowhead to alternator >I bar to rev counter wire.
I don't have wiring diagrams for your car so I cannot be sure about the above, but it is a possibility.

 

Last edited: Jan 27, 2015

Saint.V8

Dyed-in-the-wool 100% RR Junkie

Full Member

• Jan 27, 2015

• #8

Datatek said:

Could be a diode gone in the alternator, you could try an external 1N5401 diode in the alternator wire with the diode connected arrowhead to alternator >I bar to rev counter wire.
I don't have wiring diagrams for your car so I cannot be sure about the above, but it is a possibility.

Click to expand...

Think i have the diagrams somewhere....more rhan happy to dig out and you can take an educated look...

 

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dontlikewelding

New Member

• Jan 28, 2015

• #9

All test done with ignition OFF

Right then- pull the ECU out and the voltage disappears.

Pull the relay out and the voltage also disappears.

The orange wire has the 12v feed from it, once the relay is plug in the Orange wire, the purple wire and the red/grey wire all have 12v going to them which to me seems a little odd- these are the terminals runing along the center of the relay.

Any thoughts on this one?

 

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dontlikewelding

New Member

• Jan 29, 2015

• #10

EAS relay AMR 1111 appears to be the cause

swapped the relay with one from the LSE and the voltage has no longer reaches the alternator down the rev gauge wire.