2.5 NAD won't crank

[D Andersen]

My poor beat up MOD 90 won't wake up from its hibernation in a carport. I was starting it every 2 or 3 weeks all winter but in late January it wouldn't crank.

My electrical system is in quite poor shape but it was running well last summer and fall. I have good voltage at the glow plugs and at the starter. The dash lights come one as normal and all the external lights work well. I tried a different battery - no change.

One relay contact has fully corroded away - I can't find any copper in there. It is the right most one in the photo. Yeah, the one with a pile of green oxide on the transmission hump below it. What do these relays do? Are there other relays to check somewhere?

[red90]

Try applying power directly to the start contact on the starter solenoid. The wiring depends a bit on what year is your truck and if it was military. Earlier truck had power straight from the ignition switch to the starter solenoid. Later trucks have a relay in the circuit. MOD truck "may" all have the relay, I'm not sure. The wires to the solenoid should be white with a red stripe. Not sure if you can see what goes to what relay.

[red90]

For reasons nobody understands, Land Rover does not seems to have ever put a diagram showing which relay is which in the manual.

I just went and checked on my ex-MOD 90 and the 2nd and 3rd relays from the right need to be in for the starter to crank. The far right one had not effect on starting. If you undo the two screws on the top of the yellow block, it should come off and you can see the wires and trace colours.

The military wiring schematic is here: http://alre.club/Manuals/Defender%20FFR ... iagram.pdf Be careful as it can't be 100% correct as I need two relays to crank and it only shows one....

[D Andersen]

For reasons nobody understands, Land Rover does not seems to have ever put a diagram showing which relay is which in the manual.

I just went and checked on my ex-MOD 90 and the 2nd and 3rd relays from the right need to be in for the starter to crank. The far right one had not effect on starting. If you undo the two screws on the top of the yellow block, it should come off and you can see the wires and trace colours.

The military wiring schematic is here: http://alre.club/Manuals/Defender%20FFR ... iagram.pdf Be careful as it can't be 100% correct as I need two relays to crank and it only shows one....

The internet doesn't have that much on relays either. Good to know your experience. My screws are quite corroded so I have to find the exact right screwdriver to attempt extraction. I gave it a half hearted attempt on Sunday.

Thanks for that diagram. I have been using that for a while now. I will try your suggestion with power right to the solenoid next weekend.

My truck is a 1991 MOD 90 from Suffield. It ran strong all last summer.

[red90]

Mine is a 91 from Suffield as well so it should be those same relays.

[D Andersen]

I got the whole fuse and relay panel off and what a mess. Corrosion and some loose wires. That said, the white with red has 11 something volts at the relay, and 11 something at the solenoid. I connected battery power directly to the solenoid and nothing happened. Sounds like a starter rebuild is in my future.

Any advice on roll-starting the truck?

[red90]

Just drop the clutch in 3rd.

Hit the solenoid with a hammer....seriously. They get stuck.

My suggestion for a starter if buying new and not repairing: http://www.defendersource.com/forum/f9/ ... 69367.html

[D Andersen]

So just bang the solenoid housing? Steel hammer OK? I'll give it a go.

[red90]

Yes or the starter motor.

[swamijake]

It is surprisingly easy to push start so long as you enough juice to cycle the glow plugs. Also, the starter is really easy to clean up so you probably just need to take it out, clean the brushes and contacts and put it back together.