Hello all.
I have a Terrano 2 SWB 2.7TD which to be fair has given me quite a few years trouble free motoring. However..........
The other day the battery was flat, I put this down to the cobination of cold, lack of use over the Xmas period and short journeys over the last couple of weeks. Normally I do around a thousand miles a week.
Anyway, I put the battery on charge last night and this morning it was still low. I'm sure the battery is ok, its a heavy duty battery which is only 6 months old!
This is what happened next.
I called out the AA home start service. The mechanic told me that the battery was fine and that the alternator was to blame. He did perform a lot of checks to his credit and said that the alternator was only delivering around 12.6v to the battery which he told me wasnt enough.
The curious thing is though, the battery light on the dash doesnt come on at all. If I turn on the ignition but dont start it you would normally have the battery light lit up until i fire up the engine, then it would go off. problem is, it doesnt light up at all. I have removed the dash and checked the offending bulb bu it seems to be ok so there is no power getting to the bulb either. This makes me wonder if its something other than the alternator like a broken relay maybe?
All the fuses (according to the AA man) are ok so thats not the reason the battery light isnt lighting up.
Anyone come across anything like this before or have any ideas?
Cheers, Chris
Edited by Dynamic Dave on 04/01/2008 at 18:43
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Chris
The bulb is fed by the ignition and earthed by the, static, alternator. Once charging, the bulb gets battery voltage on both sides and thus goes out.
I can't remember the alt plug wiring for these; but one may be the warning light and earthing it [through another bulb for safety] should prove the dash bulb/circuit. [There may be a label on the casing with the terminal functions.]
Frankly; sounds like shot brushes and time for a re-con unit.
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Cheers for that Screwloose :)
One other thing I forgot to mention though. earlier I took the car for a drive of arounf 6 miles. When I got back I popped the bonnet and checked the battery. The battery was warm so to speak, suggesting that it was charging maybe. Does this make sense, would the battery get warm while charging or is this another symptom of the problem overall?
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Not a known test for the efficacy of the charging system - it get quite hot under the bonnet of a TD.
Have a look for that label [by the small-wires plug on the alt] and tell me what it says.
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Folks,
Have had this problem too (similar to this and the Terrano battery drain one too).
Similar issues (e.g. no problems for years, short journrneys, swapped a battery 2 monts ago, checked alternator, etc).
Not a mechanic (electronics) but looked into the electrics a bit. Read a manual (I got hold of on the web) and started to understand the issue a bit better (but not fixed yet)...
As with "Battery Drain" post checked current draw when off. Similar but found pulsing every 3 or 4 seconds to 0.2A (didn't think that duty cycle was bad enough to drain battery, it's probably just the alarm system or something like that).
Observed a few things checking when running...After starting alternator would only get to 11.5 to 12.3Volts....until a few minutes had passed and then would jump to 14.5V ??!! Now I understand why. The EMS monitors the engine temp and keeps the glow plugs on until the engine gets above about 50degC (or a certain amount of time)! That explained the lower voltage suddenly increasing. So even though you're not supposed to turn the engine over until the orange glow plug indicator goes off, the EMS keeps them on anyway (so don't leave your ignition on for a long time without starting the car for one thing).
Does it explian battery drain due to short journeys...maybe...
Also noticed that when the car's hot, if you turn on the ignition and leave it you hear something switching on and off. Traced this to the glow plug power relay (in the wing right beside the battery) That's what prompted me to dig deeper into the operation of the glow plug system. Also made up a ammeter (0.02ohm power resistor to use with voltmeter). This indicated currents ranging from about 100A dropping down to about 60A after the glow plugs had been on for 5 to 10 seconds. I don't know what the current draw is supposed to be, but I think that's quite high considering there's only a 100A fuse in line. So I'm starting to think arounf there being a glow plug that's got a few shorted wires and drawing too much current.
Anyway all of this is interesting but doesn't fix the car. I now have 4 new glow plugs and (even though the car's only got 34K on the clock) I'm going to change these first (then remeasure the current). If that doesn't fix it maybe it's a dodgy glow plug relay.
I'll let you know...
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Scottie
There's nothing that jumps out as being abnormal in that piece. High amp draw to the glow-plugs is not unusual [the fuse is 100A continuous - 200A immediate blow.]
Has this one got a metal battery clamp? Surface discharge across a damp battery top is always a possibility.
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Screwloose,
No the clamp is at the bottom of the battery. As for the battery itself it's 70AH (the one I replaced was only 65AH). Queried this with Nissan parts as they showed Terrano batteries ranging from 60AH up to around 100AH!!! Couldn't get a definative answer so got something relatively low cost as I wasn't 100% sure it was the battery (as the heavy duty batteries were about 14" long which is way too long for my battery tray).
Short journeys aren't unusual for us and this is the 4th winter we've had the car (and it's only recently thet we've had the battery draining uissue).
Thanks again...
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Hi, I believe this is a common problem. I'm on my third alternator and third battery!
And there is NOTHING wrong with either of them.
I have just today checked if the glow plugs were turning off, and hello! they are staying on! and sucking more juice than the alternator can supply.
This can be easily checked - either with a multimeter at the glow plug rail, or multimeter or LED battery/alternator tester on the battery locate the 80amp fuse for the glow plugs and pull the fuse while the engine is running - my bet is the battery will instantly be charging normally, and show low volts when the fuse is reinserted.
On my Terrano, the fuse box is half way between the battery and the fire-wall.
The glow plug relay is between the battery and the fuse box - the relay clicks in and out with the fuse removal, which makes me suspect the glow plug controller.
I haven't located the controller yet.
The American workshop manual does not cover the diesel engine model.
The Nissan diesel engine manual does not cover the electrics (glow plugs).
If I can not locate or repair the glow plug controller, I will simply add a small electrical kit-set timer, at the fuse/relay, to turn of 15 to 30 seconds after the ignition is turned on.
Hope this gives an answer to this frustrating (and expensive) problem.
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Hey, just an update!
Did you hear the one about the Terrano with a charging problem?
Just fix it by replacing the thermostat!
Seriously - check your temperature gauge does it take ages for the needle to barely get off cold? (and is the heater useless?)
The needle should get to just below half way in 2 or 3 minutes.
If the thermostat is stuck open, then the engine does not get up to temperature.
The glow plug control senses the engine temperature is cold, so the glow plugs stay on for an extended period of time (sometimes 10 to 15 minutes) - short trips particularly in winter, with more headlight driving - the alternator can't keep up with the current being drawn off and from time to time you will end up with a flat battery!
A thermostat is cheap, and easy to replace (three bolts and about a half litre of coolant - I pumped the coolant from the top of the radiator, and didn't spill a drop when the thermostat housing was removed).
Sure enough, as the engine temperature reached about 50C, the glow plugs turned off.
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