Please Help, I'm no electrician !!!!

[bluestone1968]

Hi guys
I've got a 1989 SJ410 with a strange gremlin.

When I turn on the headlights the fuel & temp guages on the dash increase and when I put on the hazards or indicators the dash and headlights flicker. It seems like the voltage drops ?
I have disconnected the battery when the engine is running and it is still the same, I also disconnected the alternator and ran the engine with the battery connected, but still exactly the same ?

I really don't have a clue where to start, please help, its due for an MOT next week.

Thanks.

[carnut]

sounds like you have a earth proplem.. check your earth connections under the dash,, also remove your clocks, and check the connections.
andy

[bluestone1968]

Cheers andy, I'll take a look tonite.

[muddy kev]

hi, what ever u do don't run the engine with the battery disconnected as this can easily damage your alternator.
if its starting ok, ie the starter cranks the engine at normal speeds, but it is effecting your dash and head lights then its probably a bad connection on the body earth. check where the lead goes from the negitive battery terminal to the body.
if that is ok check the main feed connections into the fuse box and at the ignition switch.

cheers kev.

[bluestone1968]

Hi Andy & Kev
I checked all the connections around the engine bay and stripped out the dash last nite, all the connections seem fine, I even stripped the fuse box, again all the connections where fine. I also discovered that putting on the heater fan causes the same problem, any sort of draw on the electrics make the guages rise, also the engine revs rise with the heater fan on ???
When I get home tonite I will strip and check the main body earth.
Any other ideas, this is really foxing me.

Many thanks,
Gareth

[Henry]

Are you sure the alternator is working?

Does your 410 have a brake servo?

Henry

[bluestone1968]

Hi Henry
Yep, the alternator is charging.
Yes it does have a brake servo.
Any ideas ?
Thanks,
Gareth

[Henry]

I dont know if they will start without the clocks in or not but i would be tempted to take the clocks out (only 4 screws) and then try it. On the sjs the loom comes through the bulk head n the passenger side. It will be something so so simple, its just hard to say without looking at it.

Henry

[carnut]

behind the glove box you might find the headlight dip/high beam relay, (silver box), try disconecting that. i had a fault on a sj410 with lights, that turned out to be a wire backfeeding live from the ign switch..
andy

[muddy kev]

hi, might look ok but u need 2test circuits 4 volt drop, if u have a voltmeter. start your engine then connect voltmeter from negative battery terninal 2 body of car, shouldn't read more than 0.5 of a volt. u can then check from battery positive 2 fuse box feed and ignition feed, again 0.5 volt max. where in country ru? i'm in brighton happy 2 sort it 4 u if your near.

cheers kev.