No power, main relay, fusebox issue?

Discussion in 'Mech Tech' started by chewabledrapery, Feb 6, 2020.

  1. Hey all,

    76 bay issue.

    Just tried to start the bus after its been sat for a good while, turned ignition on, had oil and alternator lights in the dash, I heard the fuel pump cycle and prime (i've converted it to megasquirt efi) but when I tried to crank the engine the entire power went dead.

    I have no lights, no fans, no wipers, no dash lights, no crank, zip...

    State of play :-

    - Checked all the fuses
    - pulled and then replaced the fuses
    - Using a meter shows that some have voltages at them
    - Battery is always trickle charged and is showing 14.4v
    - Van is stored in my garage which is part of the house so relatively damp free, and no rain ingress possible.
    - Battery terminals and clamps are clean and tight.
    - Battery to chassis earth cable is clean, good nick, dry, not rusty, bolt is tight

    If I pull the hazard switch i can hear the hazard relay buzzing, then when i turn the ignition on the dash lights come on and the fuel pump tries to prime but i can hear it glitching and the dash lights flicker, trying to crank kills it dead again.

    Any ideas??

    Is there some "main relay" in the fuse box? Is the fuse box possibly knackered? Is it just one main fuse i've not checked properly?

    I'm pretty sure the van used to "click" when i turned the ignition on and it has been fine for years i've never experienced any intermitment power issues.

    The fuse box is a bit manky though and has at least 2 semi melted fuse terminals...

    Has anyone has any joy replacing the fusebox with a blade terminal version? Is that even a thing? I'll have a look to see if there are replacements even if its an OE bullet fuse type it might be the way to go.

    I know this is probably one of those "well you'll just have to pull the fusebox and trace all the wiring" kind of problems but i thought i'd ask in case i'm missing something obvious or its a common fault i'm unaware of.


  2. meter your battery before you start pulling things apart
    paradox likes this.
  3. Flat battery or under 10v
  4. Try cleaning the battery cable where it joins the starter motor
    cunny44 likes this.
  5. if it was ok before duff battery or stuck starter would be my guess.

    when you try and start it does the dash lights dim
  6. Hit everything with a big hammer.
    MorkC68 likes this.
  7. Thanks for the input, as i stated the battery is trickle charged and at 14.4v


    It all points to the battery, going back out after leaving it and there was a bit more life in it, i've been trickle charging this over the winter with a cheapo aldi battery charger, i have a optimate on the leisure battery.

    possible that even though its reading 14 v its got no current capacity due to sulphation I've bunged my optimate on it to see if it can recondition it, if not then its a new battery :(
    Last edited: Feb 6, 2020
    Podrr likes this.
  8. davidoft

    davidoft Sponsor

  9. Deano,

    I'll try and be constructive this time...
    Which fuses are melted?
    Sounds like the starter may be stuck - Pop it in gear and rock it forwards and back a bit as this may free it. Also (disconnect the battery) give the starter and solenoid a few whacks with a hammer.
    As Davidoft says - it could just be the battery connections too.

    Once you have told us what the fuses are we can progress :)

    chewabledrapery likes this.
  10. Loose battery terminals ..
    Battery trickle charged until "boiled dry", as trickle charge should be more like 13.8 volts long term.

    14.4 is " charge equalization" and should only appear for a few hours before the charger drops back.

    Get the battery load tested. It sounds like either it has no capacity or you need to give the battery clamps a tap with a hammer to break the oxide ( might also be reason for 14.4 volts observed. Check the battery post voltage as well as the clamp voltage. )

    I once borrowed a motor boat moored in a lake in Ireland so tools were a long way away. I spent ages trying to start it, all voltages good until I turned the key. Turned out the boatyard had left the battery clamps slightly loose and tapping them on with a bit of wood fixed it.
    Last edited: Feb 6, 2020
  11. Thanks, checked that and its all brand new starter, cables etc. I rebuilt it all a couple of years back, the make terminal on the starter is clean, bright and tight!

    i'll investigate the battery its possible its that as even though its been trickle charging all winter i was using a cheapo aldi charger, its possible it may have been doing naff all

    thanks everyone!
  12. Mystery solved!

    Its the battery, the cheapo aldi trickle charger must not have been working or its knackered the battery.

    I feel a bit thick for not thinking of this, obviously i just assumed the battery was charged due to using the charger, after taking off and reclamping the battery terminals i used my jumper leads to connect my leisure battery to the main battery and everything works, hazards, lights, ignition, ECU, fuel pump etc.

    Obviously i didn't try to crank it as I don't want to knacker the leisure battery...

    So, i've stuck my Optimate charger on the starter battery to see if it can fix it, its rescued batteries in the past, may not work but worth a go, in retrospect i'm so glad i'd left the Optimatre on the leisure battery all winter as i only replaced that battery last summer and i would have been angry AF if that was dead.

    Might save up for another Optimate charger they are really good, will bin the aldi rubbish, I should have known better :(

    Thanks for the help everyone :)
  13. Can you put jump leads on the leisure battery and see if that starts it.
    chewabledrapery likes this.
  14. Woops, too late!:)
    chewabledrapery likes this.
  15. Thanks Chris, yeah it was the battery, i knew the starter was OK as i had to rock it back and forth in the summer o get it back into the garage as it got stuck in reverse and 1st and the diff was locked!

    I'm taking the box out and sending for a rebuild in the spring as the synchros and selector forks seemed to detonate last summer leaving me with only 2nd gear, which was fun, luckily i was only a mile from home when i lost 1st, 3rd and 4th ha ha

    thanks for the advice :)
    Podrr likes this.
  16. Oh bigger - I've been using an Aldi one on my MG all winter - hope it hasn't knackered mine too. Seems OK just using it on the VW leisure battery every few weeks though
  17. Dead battery. There is no "main fuse". If the battery's had it, anything that places a significant load on it will drag the voltage down
    chewabledrapery likes this.
  18. Sounds like his wasn’t set to trickle charge if it was putting 14.4 volts in.
    chewabledrapery likes this.
  19. Any charger can still destroy a lead acid battery battery long term if it insists on putting out enough current to give 14.4 volts.
    This may be due to for instance using a sealed/gel battery setting where the gases released are forced to combine under pressure at the higher voltage.
    Or its just tat.
    You may be able to top up a trickle charged to death battery with distilled water if it isnt sealed.
    A fully charged battery should be full of quite dilute acid, the sulphate should be on one of the plates.
    chewabledrapery likes this.
  20. The Lidl and Aldi chargers will drop to a float charge after a bulk charge

    There’s a possibility the battery was knackered before hand and the charger has carried on with the bulk charge.

    Another possibility is the mains power has dropped out for a short period of time
    With the cheaper chargers you have to manually set them to start charging again after a power outage where the cteck ones immediately start charging again once mains power is restored.

    Sent from my iPhone using Tapatalk
    chewabledrapery likes this.

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