Loss of electrical power to all fuses save interior lighrs (fuse #1)

[Steven A]

Hi All
 
Prior to having to pull half the dashboard out (again) to access the ignition switch, would like to know if anyone else has encountered the following (RHD 1964 230 SL) electrical issue and symptoms.
 
Vehicle totally lost electrical power, would crank very nicely but no power on ignition coil., fuel pump. Instrument lights etc.   To make it more challenging, occasionally (and randomly) all power is back to normal if key off and then go through ignition switch to power on and cranks/starts.
 
New ignition switch fitted couple of months ago as the previous ignition switch became U/S.     
 
OK, diagnostics to date:  when no power to fuel pump, ignition coil etc (this is with key in “ignition” position prior to cranking), there is power to #1 fuse (interior lights etc) and no power on the remainder of the fuses.   However....if jump from positive side of the battery direct to (say) fuse # 4, all comes good again, power to fuel pump,  engine starts, instrument lights et al work.
 
Current plan is to redo all the electric connections at the ignition switch and see if this fixers it – if it doesn’t then replace the ignition switch.    Whilst could replace the ignition switch at the same time as redoing all wiring connections at the ign switch, this wouldn’t iron out which was the culprit
 
Appreciate any thoughts and suggestions prior to having to access the ignition switch assy.
 
With thanks
 
Steven

[ja17]

Check the electrical connections on the headlight switch also.

[Ross Parker]

Hi Steven....how did you make out?
I've got a similar problem, that I'm still 'deep into it' !
I've got a 68 280Sl with auto transmission, that wintered well and started up a month ago just fine. Starting and driving around we no problem until 2 days ago. I did a warm up run, turned it off, added transmission fluid, then tried to start it 4 hrs later. I had NO power anywhere, except for fuse #1 !!!!
Engine would not crank, horn would not blow, headlights would not come on, fuel pump is not humming.....the battery has 13.5 V. There is no voltage to the fuse panel except for fuse #1. Ground from battery to frame is good. I've got 13.5 V at the alternator and at the starter solenoid. II've also got 13.5 V. at that little goofy plastic connection terminal bracket that mounts on the front of the transmission....2 wires hot that are joined, 2 wires to ground that are joined)
Any ideas?....could my problem be a faulty ignition switch?
I'm going to lean on the transmission leaver, and try N.
I'm going to smack the starter motor with a hammer and 2"x2"
I'm going to check the connections on the ignition switch
Will report back.
It troubles me that I've got no power to the fuse panel, except for fuse #1 !!.....Ross

[ja17]

Check the battery connection. If you have non-original replacement ends on your battery cables, take them apart and clean the connection where the cable clamps to the replacement end. Next check the connections at the terminal block on the oil pan, also the connections at the starter itself.

[Ross Parker]

So, I fixed my problem, but have created another one (for your suggestions, please)
First the fix was: the flippin' battery was dead ! (even though the VOM and battery charger said it was not dead)
But, when I was reconnection wiring that had been disconnected, between the battery and the starting motor, I created another problem.
The problem is that the generator light is now on, all the time the key is on, and at all RPM's.
It's not a weak red, it's FULL ON RED !!
And, if I disconnect the battery ground when idling, the motor stops immediately.
When I was reconnecting the 2 hots and 2 grounds to that little 'goofy' terminal block at the front of the oil pan (underneath, front of engine) I caused a brief short. Well, it did spark.....OK, a small spark. But it could have blown a fuse somewhere. (fuse #2 is just fine, and clean)
So, is there a fuse somewhere else?
Did I probably fry a diode in the alternator?
I'm going to check the connections on the alternator first, but, I wasn't in that area when I was chasing the "car won't crank" problem.
Any ideas.....much thanks....Ross Parker 68 280SL Victoria, BC

[Steven A]

Hi All

Thanks for responses, appreciated.

Redid all the connections (years old) on the wiring connecting to the ignition switch (rather than replace the ignition switch...it was reasonably new, and if replaced the ign switch and redid all the connections then had 2 variables in play).

So far, all good! (having said that, there is now a jumper lead with couple alligator clips in the spares in the trunk...direct from +ve terminal on battery to any one of the fuses with the exception of #1 fuse works fine as a bypass/limp home.  Just get some odd looks when you have to open the bonnet to disconnect the jumper cable to turn off engine!)

With thanks

Steven

[jpinet]

So, I fixed my problem, but have created another one (for your suggestions, please)
First the fix was: the flippin' battery was dead ! (even though the VOM and battery charger said it was not dead)
But, when I was reconnection wiring that had been disconnected, between the battery and the starting motor, I created another problem.
The problem is that the generator light is now on, all the time the key is on, and at all RPM's.
It's not a weak red, it's FULL ON RED !!
And, if I disconnect the battery ground when idling, the motor stops immediately.
When I was reconnecting the 2 hots and 2 grounds to that little 'goofy' terminal block at the front of the oil pan (underneath, front of engine) I caused a brief short. Well, it did spark.....OK, a small spark. But it could have blown a fuse somewhere. (fuse #2 is just fine, and clean)
So, is there a fuse somewhere else?
Did I probably fry a diode in the alternator?
I'm going to check the connections on the alternator first, but, I wasn't in that area when I was chasing the "car won't crank" problem.
Any ideas.....much thanks....Ross Parker 68 280SL Victoria, BC

Ross,
have you fixed that problem? Sounds like a bad alternator to me...