Electrical Problem - 60 Series LandCruiser

Submitted: Friday, Aug 12, 2011 at 15:56
ThreadID: 88435 Views:11779 Replies:7 FollowUps:4
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G'day Forum - A question for auto-electricians online

Some time ago I took my 60 Series to an auto electrician to fit extra spotlights and a second battery. Now, this is my weekend car and doesn't get used all that much but the problem is not a flat battery.

After the auto electrician completed the work, I noticed that when I was night driving the volt gauge was only putting in about 12.6 to 12.8 volts and if I turned the spotlights on - it would go lower, turn the spotlights off - the volts would pick up, turn the headlights off - volts normal.

Took vehicle back to auto electrician who said generator stuffed - new generator installed. Result -same problem, no difference. Auto electrician said the new generator was faulty - another new generator installed. Result -same problem persisting.

I adjusted the regulator and that helped a bit but when I put the spotlights on - same thing, voltage too low to properly charge the battery.

Took vehicle to another auto electrician who told me voltage regulator faulty. Bought a new regulator - works perfectly with lights on high and low beam, turn the spotlights on- goes down hill again to below 12 volts. But even worse with the new regulator with all the lights off it is pushing out over 15.5 volts, sometimes 15.8 volts which is far too much.

I have disconnected the second battery and all the accessories but still the same problem.

So, new generator, new regulator, new battery - I can't think of anything else to look for.

Any help from a sparky would really be appreciated as the only alternative I have now is to put the old regulator back on that works OK with no lights on and only drive in the day.

Thanking you in anticipation

The Major
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Reply By: franken - Friday, Aug 12, 2011 at 16:34

Friday, Aug 12, 2011 at 16:34
Sounds like a bad connection to me (check the battery, alternator, regulator connections) or a high impedance cable between the alternator-regulator-battery, measure the voltage drop across all these points with the headlights and spotlights on.
AnswerID: 462428

Reply By: Member - Joe F (WA) - Friday, Aug 12, 2011 at 16:38

Friday, Aug 12, 2011 at 16:38
G'day "Major"

This is only an educated guess but your vehicles electrical problems are symptomatic with a poor battery earth connection ~ check or renew the "Major" earth cable from the original battery to the vehicle body and also the engine to chassis earth cable if it actually still has the original one fitted.

Obviously revisit the new batteries earthing point(s)

The older Land Cruisers, especially the diesel engined ones had fairly poor battery negative cables and connections.

Safe travells: PICTOURS
AnswerID: 462429

Follow Up By: olcoolone - Friday, Aug 12, 2011 at 16:44

Friday, Aug 12, 2011 at 16:44

Everyone forgets the factory earth point could be at fault.

Earth problems always show up under load.
FollowupID: 736234

Reply By: Member - C J- Friday, Aug 12, 2011 at 21:12

Friday, Aug 12, 2011 at 21:12
Hi Major All I can say is that cruisers have a funny system (I had a 60 series and fitted spotlight also) headlights have 3 wires, High and Low beam and Earth, Cruisers have power in one line and earth in the other two.(now please forgive me as that now sounds funny)It has been a while since the 60 series, and I can't explain how to wire yours up now, but if you pick on the wrong you will have electrical problems. Sorry I can't be more postive my help.
AnswerID: 462457

Reply By: TheMajor - Saturday, Aug 13, 2011 at 12:24

Saturday, Aug 13, 2011 at 12:24
G'day Frank, Joe and Colin,

Thanks for your reply lads, I really appreciate your advice.

The first thing I will be doing is cleaning the battery connections particularly the earth lead and other wiring. If that does not work I will follow some other advice I have received that the generator on the 60s series may be struggling to light up the spotlights. I have 4 spotlights plus the driving lights, and thinking about it now, it was not until after those lights were fitted that I detected the problem. I only use the car as a second car and it would have been some time after the spotlights were fitted that I actually used them.

It is a shame that the old fashioned detective tradesmen are disappearing.

Once again thanks very much for your advice


The Major
AnswerID: 462491

Follow Up By: PeterInSa - Saturday, Aug 13, 2011 at 13:13

Saturday, Aug 13, 2011 at 13:13
I thought replacement alternators on the 60 series were 150 amp jobs, which should be an issue with the extra spoties.

FollowupID: 736293

Follow Up By: PeterInSa - Saturday, Aug 13, 2011 at 17:32

Saturday, Aug 13, 2011 at 17:32
I thought replacement alternators on the 60 series were 150 amp jobs, which should NOT be an issue with the extra spoties.

FollowupID: 736308

Follow Up By: TheMajor - Saturday, Aug 13, 2011 at 20:07

Saturday, Aug 13, 2011 at 20:07
G'day Peter

Thanks for your reply. What I've done now is cleaned all the earth and positive connections to the batteries and taken off the new voltage regulator which was pumping out too many volts for the 60 series. I've put the old one back on. Things are now working ok concerning the original lights high and low beam, as I'm getting a reading of 13.8 - 14.2v, however, as soon as I turn the 4 spotties on things die in the bum.

Anyway, I'm going to get an amp meter and check out the maximum amps from the alternator, bearing in mind this is the second new one I've had in the last couple of weeks. I'm pretty sure the alternator is pumping out the maximum.

I'm still experimenting and I really appreciate your advice.
Thanks Peter,

Catch you down the track sometime


The Major
FollowupID: 736313

Reply By: Shaver - Saturday, Aug 13, 2011 at 14:17

Saturday, Aug 13, 2011 at 14:17

I had a 60 Series Sahara (aftermarket Turbo) Diesel & experienced the same problems as yourself. Was very disconcerting on a trip with Spotlights on & fridge going also. I also had a 2nd battery in parallel. The voltage would go very low with all on & go back up slowly at day break with lights off. The vehicle always started though with this anomally. The Alternator eventually went at about 160,000ks & the new aftermarket one with a higher output still did the same, so you are not on your own. I checked the output at the battery with a Multi Meter & it was up around the 14.8 with a rev, so it appears to be a conflict between the meter & the vehicle gauge. I was beginning to think Toyota was maybe taking the power for the instruments from somewhere at the back of the vehicle with a corresponding voltage drop. I never worried after that as I never had a flat battery.
AnswerID: 462498

Reply By: disco driver - Saturday, Aug 13, 2011 at 23:01

Saturday, Aug 13, 2011 at 23:01
Have you calculated the total draw on the system when you are lit up like a Xmas tree?
2 Headlights @ 55w
2 Driving lights @100w
4 Spotlights @100w
2 sidelights @5w
2 tailights @5w
4 Instrument panel lights @5w

Not allowing for any other power use that's a total of 750w.
Divide that by 12 gives you an approximate amp draw on your battery of around 62 amps.
It doesn't leave a lot for recharging the battery and if there are any points of poor connection they will make the problem worse.

Clean all the cable connections first up and then fit a bigger alternator or turn off a few lights.


AnswerID: 462526

Reply By: trainslux - Monday, Aug 15, 2011 at 21:16

Monday, Aug 15, 2011 at 21:16
Are the lights running off relays, or patched into the old headlight loom?

Toyotas used to run the light circuit load through the light switch, which would often fail, or become a source of problems.

Best bet if not already done, is to use the light circuit to activate relays for each bank of lights, ie low, high, and spotties.

And dont skimp on the earth wire returns to your battery, or common earth point on chassis directly connected to the battery.


AnswerID: 462698

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