Electrical system failure

[Manton M-Rod]

Does anyone have experience with this problem?
Attempted to start my 1998 M-roadster the other day. The dash instruments powered up as usual but when I rolled the key to start, the car lost power. No start no dash lights no electric system. The battery checked good with good connections. I've replaced the ignition switch but the problem remains. TIA

 

[IanA]

This happened to mine last week. I hadn't driven the car any distance for a month. It started OK and I drove 17 miles with headlights and blower motor on. Later that evening it displayed your symptoms. A jump start to the battery started it first time. I drove home using lower gears than usual and avoided using main beams and it has started OK since.

 

[colb]

Check out the explosive disconnect on the battery positive terminal is tight and fully home, they do loosen up over time and cut power to the car. Tap it in with a small hammer and a punch to ensure its fully home.

 

[Manton M-Rod]

Thanks,

I did find the extra lead at the + battery terminal had lost its torque. Problem solved! What I found confusing was having proper voltage at the battery and the B+ terminal under the hood, but losing voltage at B+ with the ignition key on. Now I know.

Check out the explosive disconnect on the battery positive terminal is tight and fully home, they do loosen up over time and cut power to the car. Tap it in with a small hammer and a punch to ensure its fully home.

 

[colb]

Dodgy connection at the battery probably managing to send 12v to the underbonnet terminals but switching on putting a load on it and it couldn't cope with the extra demand on the circuit. Glad you got it sorted.

 

[IanA]

Always worth checking the battery connections before any troubleshooting.