Split charge relay-alternator and a/t temp lights on...

[andy_enuff]

Just refitted my old split charge relay to my 3.0. Located the alternator wire that is only positive when the alternator is providing charge (yellow and green if I remember) and rewired everything so that the alternator charge, starter are coming from the passenger side battery. All seems to work fine, switches at the correct times, splits correctly etc. Only problem is I now have very feint battery, a/t temp and couple of other warning lights glowing dimly when the engine is running. Not obvious when it's daylight, but visible at night. Any ideas what I need to do to sort that out?

[Artful_dodger]

Just refitted my old split charge relay to my 3.0. Located the alternator wire that is only positive when the alternator is providing charge (yellow and green if I remember) and rewired everything so that the alternator charge, starter are coming from the passenger side battery. All seems to work fine, switches at the correct times, splits correctly etc. Only problem is I now have very feint battery, a/t temp and couple of other warning lights glowing dimly when the engine is running. Not obvious when it's daylight, but visible at night. Any ideas what I need to do to sort that out?

I had a similar problem recently with glowing warning lights, I found a lose earth behind the speedo cluster, tightened it back up and been ok since.
Now the only problem is the rev counter doesn't register on tick over but seems to read too high when driving, It's baffling me

[andy_enuff]

soooo....

I've been busy do lots of checking...

Checked the battery that the car starts from: Slightly low on water and discharged. Charged on battery charger and held voltage fine, load tested and held constant high current. Battery seems ok.

Checked battery for accessories. After an initial issue with the secondary voltmeter I have installed appearing to show the same voltage as the starting battery I managed to isolate an earth issue with the voltmeter which now reads the correct voltage. Accessory battery ok.

Current supplied to the 180A relay seems to be 220ma - maybe not nough to switch properly but there is only a 7.5v drop across the relay coil (from the alternator sense wire to body). All negatives to body have been checked and all are fine.

So... I am stumped - unless the erlay is screwed, or the sense wire fro mthe alternator is not capable of supplying more than 220ma then I am not sure where to go... other than connecting the relay coil directly to a seperate 12v battery and measuring the current to see if it is greater than 220ma....

Any ideas?

Just to state - there were no dash warning light issues befor doing this - so unlikely to be a dodgy earth on the dash. I suspect one of the 2 issues above - insufficient current or broken relay that still somehow switches...

Also, when running at idle, both batteries seem to be charging and show voltages that eventually end up at 14.4 volts - and both bateries hold charge to about 12.7v when the car is not running.

[BUSHWHACKER]

Try using the oil pressure switch as a relay trigger instead of the alternator.

[andy_enuff]

On another thread I've been talking about the battery voltages... but that seems to have been a didgy battery... This one I've still not addressed.. more through lack of time than anything else. Where can I best find access to the oil pressure sender line Bushwhacker? I had a quick look underneath - couldn't quite figure out where the best take off point was for the oil pressure wire...

[andy_enuff]

Any clues Mr bushwhacker sir?

[BUSHWHACKER]

Behind the ECU there are two large (one grey one white) multi-plugs.
Look for the thin yellow/black stripe wire, this wire goes to the oil pressure gauge on the dash, can't remember which plug it's in though.

p.s. It's the thin yellow/black stripe you need not the thicker one, there's one in each plug.

The tacho wire would work as a trigger too, it's in the smallest of the ECU plugs, plain black wire.

[andy_enuff]

Cheers squire. I'll have a look tonight if the weather stays ok

[andy_enuff]

Hey mr bushwhacker sir... I went out to look at this about 18 months ago and only just got back in ive found a yellow with black (the thick one you said not to use) but its at ground and I cant find a plain black wire anywhere or another yellow with black stripe in the other plug... its a gen 2.. any other clues... im stumped unless you could impart some of your knowledge or send me in the direction of the right diagram?

[andy_enuff]

So... I measured up the resistances on a std realy and on the 180 relay I happen to have for split charging. Big difference. ... so now I have a smaller one switching the bigger one using either the battery positive from the starter battery or the Alternator charge wire (switchable using a 3 way toggle switch - also has "never connected"). This little relay then switches the bigger one which is powered also off the ignition battery and now has a tiny light to show "connected".

Everything now works as it should and the dash lights are fine... Weird 180amp relay...

This setup allows the three positions from a switch mounted in the engine bay:

1. Automatic - batteries connected and charging only when engine running
2. Isolated - only charge the starter battery
3. Permanent - batteries connected as long as there is enough charge in the starter battery (if starter is too weak to start car it will usually still power the relay and allow the leisure battery to dump charge across for starting)