radio keeps resetting

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Feb 20, 2008
I am sure this is a dumb question, but I am not very smart sometimes either. I tried searching for a answer but couldnt find what I needed.
I just got a 78 fj40 last month and the other day I noticed that everytime I turn the ignition off it resets my radio presets, I also noticed that my dome light wont work anymore(stock and not the bulb). I checked the fuses and what grounds I could find but I really have no idea what to look for. This more of a annoying than anything but I dont know if it means there is a bigger problem. Any help would be great, this place really is awesome. Thanks!
You have the hot and switched wires backwards.

Sounds like your radio power wire is tapped into your ignition switch, and god only knows what else is messed with.

Look at your fuse block and see what is hacked up under the dash.

Good luck!
You can hear your radio?
thanks for the help I will check that out. But how come it worked the whole last month but not in the past few days? I cleaned the battery terminals off and thats when it seemed to start. Thanks again!
I just put a new radio in my truck and had the same problem. Look at the wiring diagram that came with your radio and note which two wires are your power wires. One of the wires will need to be controlled through the switch. The other will need power all the time, this will keep your presets, time, settings, etc from resetting.

I wired mine to the fuse careful when tying into the existing wires. :rolleyes:

First I determined which circuits on the block remained hot while the ignition was in the off position. I think it was one of the top 3 fuses on my fuse block. They are usually your head lights, brakes lights, etc. I put mine on a 20 amp circuit to be safe.

Next, I wired the radio into the radio circuit, which loses power when you turn the switch to the off position. If you are supplying your power from the original radio power source, this explains while you are losing your presets. Since the original radio was analog there wasn't any reason for Toyota to run constant power.

I ran all new wires, but this was due to the fact I installed my radio in a tuffy box.

Good Luck! I hope this helps!
I cleaned the battery terminals off and thats when it seemed to start. Thanks again!

If so, then maybe you still have a bad connection at the battery, possibly for the white wire that feeds the entire chassis. As mentioned, the radio needs constant power from the non-switched side of the fuse block to keep the presets stored in memory.
sounds like a fuse issue as said before, basically the radio has to have a constant power and a ignition power. just the ignition power will make the radio work but the constant power is what stores presets. and if i recall correctly the dome light is a constant power circuit so i would look to see if they are on the same fuse, mine were for some reason. check the connections at the back of the fuse block, but be careful i shorted out my entire harness messing with the fuse block...... i always learn the hard/expensive way

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