Voltage Stabilizer

[Big Camper]

Hi all, I have recently purchased the Yellow LWB CF camper you probably all spotted on Ebay.  Slowly working my way through the electrics and enjoying the learning and reading the forums you have all posted.
I have a few electrical problems.  Behind the dash in the mountain of wires there is no voltage stabilizer, however my fuel gauge and water temp work fine.  What led me to look for the stabilzer was this;
When I start the engine the tacho comes alive and the 'charge' light dimly illuminates, when the heater fan is turned on the tacho dies and the 'charge' light comes fully on.  As with turning on the fan, the indicators cause the tacho to die.  Is this anything to do with the missing voltage stabilizer? or can somebody help with narrowing the focus?

Thanks - Stu

[BusyKiwi]

first thing is check your earth/s 
sounds like mostly body earth but also check you have a good earth from engine to chassis.

Unless the dash has been changed the tacho is an addon which shouldn't effect anything as it just goes from the coil, only the light might be wired into the loom, again start with the earths

[Numnutz]

by voltage stabaliser do you mean voltage regulator?  if so it is easy test for this, measure the output from an active wire, if  at idle 12v or less and when the engine speed is increased the voltage increases well over 13volts = faulty regulator.
doesn't sound like that would be the problem, but you never know.  

from your post I could make a guess and say that the tacho has a problem with its wiring, and the alternator has a low output voltage, either due to age or bad connections.

I would check the earth wires on all the systems that are doing odd things (firstly the tacho), after that I'd check the wires to alternator and the voltage output of the alternator.
would also check that all wires to starter motor are tight and the earth from the battery to the body and motor to body is good.
if no problems are found there I'd start looking for melted wires/connectors, some how multiple circuits are joined together.

good luck.

Do you have a multimeter?




 

[willo]

Hi all, I have recently purchased the Yellow LWB CF camper you probably all spotted on Ebay.  Slowly working my way through the electrics and enjoying the learning and reading the forums you have all posted.
I have a few electrical problems.  Behind the dash in the mountain of wires there is no voltage stabilizer, however my fuel gauge and water temp work fine.  What led me to look for the stabilzer was this;
When I start the engine the tacho comes alive and the 'charge' light dimly illuminates, when the heater fan is turned on the tacho dies and the 'charge' light comes fully on.  As with turning on the fan, the indicators cause the tacho to die.  Is this anything to do with the missing voltage stabilizer? or can somebody help with narrowing the focus?

Thanks - Stu

G'day Stu.  Mate, Joseph Lucas (we have LUCAS electricals in CFs)  is indeed the prince of darkness!!!!  Bosch electricals use different connectors and seem to give less voltage drops.  It sounds like you may have voltage drops to the inside of the cab.  Here are my thoughts.
- there is no voltage stabiliser for the fuel and temp gauges.  they are what they are.  Jap cars have a voltage stabiliser so the gauges are 'fed' a set voltage to improve their accuracy.
- The 'bullet' type connections where the harness comes through the firewall can be part of the cause of voltage drop to the inner cab.
- The fuse box connections can be corroded a bit.  Check the rivet under the base of the fuse too.
- Check (and double check) your earths - as already mentioned.  If in doubt, run additional ones.
- You might be losing .25 of a volt through a connector and a bit more through another and it all adds up.

Go out and buy a multitester from someone like Supercheap or Repco.  Then learn how to use it.  You can check for resistance using the ohm setting and volts getting through using the DC volt setting.  Without this you are guessing and looking for a needle in a haystack.

Keep us updated how you get on.

Cheers

Neil

[ben]

i think the voltage regulator is mounted on the engine side of the firewall??

[Big Camper]

Great to get such an array of quick responses. Thanks.
I'm learning a lot here. I have a multimeter and a small amount of knowledge on how to use it.
Checked the voltages from the alternator is ~13.8V, the temp and fuel at ~10.7V, the oil and tacho at ~11.0V but when fan is switched on voltage drops to ~6V.  There is also a 'charge indicator' light on the dash, when the fan is switched on the voltage goes from 2.2V to 6.2V!  The fan switch is a single speed and a full 12V passes through it.
I have looked for the voltage stabilizer/regulator under the dash and on the firewall and everywhere and cannot find one, as mentioned earlier though this doesn't seem to pose a problem as voltage is not going above 12.8V under revs.  As a sideline, under revs the voltage drops slightly ~0.2-0.6V is this normal?

[JOE RYAN]

One thing to keep in mind is that with faulty connections you may still be showing 12v but the current (amps) may not be sufficient to run whatever is turned on.
Amp meters are usually to expensive to buy for the home mechanic and they have to be wired in series which is a bit of stuffing around, as suggested check voltage earths and connectors.

Joe

[LS120]

is the altornator a Lucas or Bosh?? if Bosh take it off & take the reg & bush unit off check that both the brushes are going in & out freely.. i had one that had gunk in one & it was causing similar probs on a LWB with a 173 in it...