Issue: no int. lights, locking, dash clock

Hi all,

Had a guy replace the old flip-down roof monitor yesterday. Put the dash together again and the head unit isn't working now, nor is the dash clock (in the MFD), the interior lights and the doors won't remotely lock/unlock. Also the boot (trunk) is locked.

One thing he did was disable the rear interior light 'always powered' (where the power for this monitor is coming from) so that the flip-down monitor only has power when the car is on (the old one could be put on anytime, so the kids had to try and remember to switch it off), and I'm wondering if that could have been the cause... breaking the circuit or something and freaking the car out.

I can drive the car fine, just not lock it etc, and it would be nice to have the HU working again (even if it's video out seems to be dead which we found out when testing the new roof monitor, but that's a different story).

Any advice appreciated.

 

Any other suggestions?

ACC fuse is fine.

 

15 amp Dome fuse had blown. Replaced, turned on the car and it blew again.

Waited a week for the roof monitor installer to have a look. A 12v power wire in the roof seemed to have been burned at the end (strange though, it was in a sheath). He fixed up the wiring, I went to turn the car on and.... nothing. Recharged the battery overnight and still nothing the next day.

Next step is to re-check the fuses under the dash again (which were fine 2 weeks ago).

 

Checked all the fuses again today (under dash and bonnet). Nothing burned out. I did see that a couple of 30 amp fuses were missing under the bonnet (not a clue why, probably never been there), the ones on the right side, where it should be 30, 30, 30, 30, 15, 10 from the bottom up. The two middle 30's were missing. So, went and bought a few just to make sure and put them in.... and back to normal (!?!). No errors, everything working (even the head unit was back).

Either in my checking of the other fuses I put one back in properly (where maybe it had been loose), or the missing 30amp fuses (which no-one took out anyway as it's only been me looking at fuses) made a difference.

Actually, I suspect the former, as before I put the 30 amp fuses in I saw that the 'door open' red display was showing, and also the light surrounding the key hole.

Or.... the Prius has a nasty sense of humour.

Next step will be to see if the head unit is actually sending video out to the monitor (which it wasn't... and the monitor is fine (tested using a video camera output)). The Pioneer could have a faulty video out, which would suck as I may as well buy some cheap chinese thing with more features and it would last as long as this Pioneer.

 

I neglected to mention I'd replaced the 12v battery as well, as I'd read here a lot of weird things happen with a dying battery.

Now the MFD is totally blank. Ironically, the only thing working in that whole unit is the clock (which wasn't working when the dome fuse was out).

All the connectors are in correctly. Not sure what the hell is going on.

As it's not an essential unit, I've just left the MFD plugged in for the moment.

I haven't checked any fuses as yet, but it wouldn't be the 100 amp, as the car starts fine. Only thing missing is the MFD. I can still control temp etc via the steering wheel controls.

 

I'd like some advice please...

Called Toyota. They haven't come across a blank MFD before, but said to bring it in and for $150 they'd reset the ECU to see if that was the issue. Also said if it's not the issue then I wouldn't have to pay.

With replacing the battery, can the ECU lose connection with the MFD?

I can get a 2nd hand MFD from a wrecker for about $180.

UPDATE: On calling Toyota again and talking to someone else, they said the ECU is reset whenever the battery is disconnected anyway. They would do a diagnostic test for the $150. Worth it?