weird dash malfunction

Post by **Clemens** » 02 Nov 2019, 11:01

A few months back the battery was quite empty I guess and after starting the 96 R after a shirt drive to back up into the garage a few random dash lights came on. I recharged the battery, all lights were gone.

Today in the morning it felt slowish on startup, thought batzery about empty from sitting for a week. (it is a Volvo battery, 3 yrs old). Drove for an hour, parked the car for 6 hours. Went to start again, turned over slowish, but fired up.

And then the dash was like a zombie. Lights on, clock working, turbo gauge working. No rpm, no coolant temp, no exterior temp, no speedo, no odometer, no fuel gauge.

Drove for 5 miles, started again, everything was fine. Is rgis a weird low battery or starter wire corrosuin issue or what else could it be? I doibt it is the ABS unit because this should not cause problems with fuel gauge, temp etc. Plus, I already fixed it twice.

btw.: wiggling the key while in zombie mode didn't change a thing.

Let the guessing begin ...

greg850r · Post by **greg850r** » 02 Nov 2019, 16:08

I would load test the battery and charging system too. It sounds very much like a low voltage situation.

Post by **abscate** » 03 Nov 2019, 04:54

Have a good look at the battery and ground cables, including the joined connection at the starter.

If that’s all good, electrical part of ignition switch, part number...

Post by **Clemens** » 03 Nov 2019, 12:29

Thanks, I will take a look at the wires and the charging system. I guess the battery symbol only comes on if the charging system is really bad, not if it is starting to be on it's way out.

Post by **misha** » 03 Nov 2019, 13:56

Battery light will illuminate when there is a permanent fault with voltage regulator or with diodes....in other words....when there is no voltage output from the alternator.
Otherwise....if b+ cable or ground cable is bad it will illuminate only if charging output is lower than battery voltage.

For example....when the car use only battery voltage to keep running and no output from
alternator.

When i had a bad b+ cable and when i had 13.1v on battery terminals the battery light wasn't ON.
I guess that it's because i still had 14-14.2v measured directly on alternator.

After replacement of b+ cable i had the same voltage reading on battery terminals & alternator.