Hi all,

disco isn’t starting. Checked the battery, it’s good. Used a light tester, starter solenoid is getting 12v. Replaced the starter hoping it was a bad solenoid, didn’t fix the problem.

- vehicle won’t come out of park
- when I turn Key to position II my radio would usually come on and now it isn’t.
- when I try to start… silence

Is this a bad ignition switch?

 

UPDATE

looked through my fuses and my 60A fuse in the engine that is entitled, “Ignition Switches” has failed.

Will replace, but do you all know what exactly this fuse is for? And anyone have an idea of why it may have broken?

Thanks!

 

if you tried to jump start the vehicle , it's possible that may have blown the fuse

 

On relays, generally a couple common things happen:

1) The most common is the electrical contacts inside get pitted (and worn) from age and use. There's a lifespan on relays bc everytime they engage there's literally a spark the moment before the contacts close. The contacts are hardened to help resist pitting, but after enough uses relays can get badly pittted and even worn away to the point where they don't pass current like they should. They have a lifespan just like other parts. You can pop the top cover off the relay and look at them. A lot of times in the field (or desert) a guy can slide some fine sandpaper between the contacts and restore them temporarily to get ya un-stranded. Relays can often work for years if the contacts are pitted and just need a good cleaning with some 600 &1000 grit sandpaper. It all depends on what the issues is.

2) The other common failure (less so in my experience) is the electromagnetic coil can fail inside the relay. Then it won't draw down the contacts like it should. A lot of times the coil doesn't outright fail but the fine wire that leads to the electromagnetic coil can corrode or break off or otherwise come disconnected from it's soldered point. In the field sometimes a guy can bridge the broken area if a person was desperate enough.

3) Another common problem is the relay doesn't actually fail, but the electrical signal to it, or the ground is messed up (weak ground or battery connections) ...or one of the terminals is corroded. Regardless, the electrical signal (or gnd) to the relay is just less than what it takes to engage it. So it 'seems' bad, but it's really too little current to activate the electromagnetic coil enough to pull down the contacts. Removing a relay or wiggling it may overcome corrosion at the relay itself or relay center. Cleaning battery terminals or cleaning engine/body grounds may restore the signal path enough so the relay will operate per normal. Sometimes a relay contactor lever can get 'stuck' open too, or stuck closed and the contacts 'weld' together. Neither is that common but not impossible. A good tap with a screwdriver handle may dislodge this issue and they can work again, sometimes for a long time.

Pop off the relay cap gently, with two small screwdrivers and inspect it. Maybe you'll find the exact problem. There are videos what to look for. You almost need to look at the contacts with a powerful magnifying glass and a flashlight, they're small. Glad you got it figured out. I just bought some new relays for my Ram Tk. There are a number of Ram owners who are seeing relays fail and no-start like you're experiencing. Can happen on a number of vehicles.

 

Thanks for that Mark, appreciate all the info.

This a 60A Fuse though… which I believe is different from a relay? A relay being the enclosed, “box” type fuses for lack of a better term.

 

The ETM Rave for '97 shows several 60A fuses in the engine compartment fuse box P125. Fuse MF 5 feeds the starter solenoid relay K137 behind the RH footwell trim panel, and also feeds the ignition switch (that feeds a bunch of smaller fuses rated 5 to 20A when the key is ON). In order for that MF 5 fuse to blow would take a pretty serious short circuit to ground, maybe in the starter solenoid coil, but could also be the wire. Be sure to measure ohms to ground on the circuit with the key OFF (it should read high ohms or infinity, when the key goes to start position III it will connect to the solenoid coil with low ohms, but should not be zero). MF 2 is another 60A fuse that feeds the front blower motor relay and nothing else, so you could swap that fuse into the MF 5 position for a test.

This info is from the '97 wiring diagrams. It's probably the same for the '99, but might be different, so it's better if you get the diagrams for your model year.

 

Hey @JohnZo thank you for that.

Replaced the fuse and it started right up. I’m liking your theory about a short in the old starter solenoid.
I’m thinking when I have some more time I’ll trace the wires coming out of that fuse and look for any exposed wire.