Fuse blows when using overdrive

[colinwoods]

Hi all,

When driving or ticking over, my IGN indicator starts to light up on my dash. Flickering but never fully highlighted... Car runs perfectly but as soon as I flick into overdrive (when driving) my 35a fuse blows and I lose indicators, fuel gauge, Rev counter, wipers and heating. I then pull over, replace the fuse and carry on with everything working fine... so long as I don't engage overdrive again.

I've removed the battery, cleaned the connectors. Repositioned the alternator to make sure the belt is tight, however I'm thinking I may have to replace the alternator.

What's your thoughts?

Thanks

[Toledo Man]

Have you taken a voltage reading across the battery terminals? Don't trust the in-car voltmeter. It could be something as simple as the brushes (a cheap and easy fix). Don't forget to check the connections to the alternator and make sure the alternator body is earthing properly.

[Tony Burd]

The wiring that goes down the gear lever probably has broken causing a short circuit when you flick the switch, check it out.

[GrahamFountain]

I have the same problem with the overdrive blowing the fuse. It sometimes happens when I only change gear - hand on top of the switch. So I'm fairly sure, in my case, it's one of the wires connecting to the switch in the gear knob shorting the feed to the solenoid to earth. However, I've looked at them several times, and put tape everywhere there looks to be a possible problem, and it still happens every so often.

Graham

[nitram]

The wiring that goes down the gear lever probably has broken causing a short circuit when you flick the switch, check it out.

. Yep I can agree ;this happened to me only I was getting a small shock every time I switched the over drive!!

[Mahesh]

Happened to me in the same way,

Initially started when overdrive switch flicked, then when changing gears.

The lead going down the gear lever had chaffed on the exit hole from the lever.

[mahony]

99.9% to be the wiring through the gearstick, has happened to me twice in sprint ownership , a very easy one to fix

[colinwoods]

Awesome. Thanks all.

I'm going to see if I can dismantle the gear knob tomorrow.
How best can I crack in?

Any pictures would be greatly appreciated.

Thanks

[AlanH]

Happened to me.

Would suggest the the first step is to lift off the top cap of the gear lever and take a look at the connectors. That's where my problem was.

[Dolly-Dimple]

Ive heard that many times in the past regarding getting a small shock when touching the overdrive switch!

[MIG Wielder]

I'm going to see if I can dismantle the gear knob tomorrow.
How best can I crack in?
Any pictures would be greatly appreciated.
Thanks

To get inside the cap you need a wide-blade screwdriver, stillson wrench or similar with a soft cloth to avoid scratching the chrome of the lower collar, bendy-nose pliers to get the top circular nut loose and to pull the terminals off.
Remove the top cap and switch by inserting the screwdriver in the slot and twisting it.

remove top.JPG (121.84 KiB) Viewed 1519 times

You can now inspect the terminals. I've added extra sleeving to mine ( the red items) where they come off the back of the switch.
One possible short circuit are is where the terminals come off the back of the switch and intermittently short to the top of the gear level hollow metal tube

terminal view.JPG (46.77 KiB) Viewed 1519 times

The circular nut inside the cap can be undone, by removing the lower chrome collar with a stillson wrench or similar. Use a soft cloth to protect the chrome. Alternatively if you have a thin jaw 5/16 in spanner you can use the flats cast into this lower collar. When refitting just engage the top circular nut by just 1 or 2 turns and screw the chrome collar up to secure it.

lower collar.JPG (76.37 KiB) Viewed 1519 times

The top of the wiring can be inspected from this point. Remove the gearlever gaiter and coin tray to inspect the lower part of the wiring. The photos are of my 1850 but the 1500 / Sprint are the same.
The reason you can get a shock off the gearlever is because it is not well earthed with nylon bushes supporting it. The back emf from the solenoid when it is switched in or out provides the high voltage which connects to the metal of the gearlever if the wiring is dodgy.

[Mad Mart]

Tony, you just need to use a 5/16" A/F spanner on the chrome collar.

[tony g]

Just a note to add, the green wire which is the feed for the overdrive and reverse lights are LIVE when the ign is on so any fiddling in there will cause a short if the ign is on.
Tony

[colinwoods]

Thanks everyone for your help with this!

I used your advice and removed the gear stick end and inspected the wiring. It 'looked' fine. I disconnected both wires and cleaned the connections, then put it back together again. The battery was disconnected so as not to hurt anything so I couldn't check to see if the wiring was faulty further down the gear stick tube. I could'nt see anyway to check the wiring down the gear stick tube? Guess I'd have to remove the carpet that's underneath the gear stick area in order to follow the cables to the gear box?

Anyways, it seems the IGN light still comes on, all beit faintly... My mind is now on my Alternator, because the IGN light is not always constant and is mostly dim. As a side note, the fuse only blows when I'm traveling and naturally looking to flick the overdrive at speed... Not when the car is stationary.

I'm perplexed. It's either a bad wire, bad connection to the Over Drive itself or Alternator, or maybe the switch has become faulty? What's your thoughts?

Thanks for all your help so far.

[mahony]

The wiring is normally faulty where it passes through the actual gearstick it's a small hole further down and you have to push the gaiter up to expose it if my memory serves me right ( if you look at the pic you can see where it passes through )
http://www.rimmerbros.co.uk/Item--i-GRID008477