No guage cluster lights, rear running lights or license plate lights

[Kiyp]

Ive got a 2003 maza b3000 ive just bought off a friend, its apparently got a parasitic draw that used to be worse till he unplugged the aftermarket stereo but its still there, as well as that the maf was bad so he replaced it and the new one quickly went bad as well, fuse 33 also keeps blowing quickly and you can smell something burning when a new fuse is put in and the lights are turned on, when its blown i have no guage cluster lights and no rear running lights as well as no license plate light so I can't really run it at night, i mentioned the first couple things because i was uncertain if they had anything to do with what is causing the issue, I haven't really seen anything quite the same on the forums but, only similar but not close enough imo im terrible at navigating forums though, any help would be greatly appreciated, im awful with electrical work lol

 

[Uncle Gump]

Just a guess but I would start by checking the radio install... to keep popping the fuse... you have a dead short to ground somewhere in the that illumination circuit.

My next guess would be a short where someone tried to tap into the illumination circuit for something aftermarket. Like toggle switch or gauge backlighting... probably right near the headlamp switch.

You can also try disconnecting the rear lamp harness in the rear of the truck. if the fuse doesn't pop with that harness disconnected... the problem is in the rear lamp harness. Also look at any kind of trailer wiring that was added.

So what I'm really saying is check any wiring that was added to the factory harness... chances are it's somewhere in the add on stuff.

 

[Kiyp]

Just a guess but I would start by checking the radio install... to keep popping the fuse... you have a dead short to ground somewhere in the that illumination circuit.

My next guess would be a short where someone tried to tap into the illumination circuit for something aftermarket. Like toggle switch or gauge backlighting... probably right near the headlamp switch.

You can also try disconnecting the rear lamp harness in the rear of the truck. if the fuse doesn't pop with that harness disconnected... the problem is in the rear lamp harness. Also look at any kind of trailer wiring that was added.

So what I'm really saying is check any wiring that was added to the factory harness... chances are it's somewhere in the add on stuff.

Thank you for the run down, ill all that and see if it works and reply back by the end of the weekend if it doesn't, im not great with electrical issues so its a big help

 

[RonD]

Diagrams below, #2 has the fuse 33 wiring, but you should look at/get both

(You can use an OHM meter vs blowing fuses to test if there is still a short to ground)

I would unplug the main Light switch, first
Then put in a fuse, see if it blows, 33 has power all the time not a key on circuit
If fuse blows then the short is between engine bay fuse box and main light switch, run a new wire

If fuse does not blow then pull it out, and plug main light switch back in
Make sure light switch is in OFF position
Put fuse back in
If it blows then light switch is the issue, not uncommon

If it doesn't blow, turn switch to Park lights only
See if it blows, if not then try Headlights, see if it blows


If battery seems to lose voltage when vehicle sits, FIRST TEST THE BATTERY, common end of life for car batteries is when they become self draining, internal short

After driving vehicle wait a few hours, and test battery voltage
12.3v to 12.8v is what you should see, WRITE IT DOWN
Unhook either battery cable, or both, but just one is fine
Wait overnight, 6+ hours, longer is better
Re-test voltage before hooking battery back up
Should be EXACTLY the same as first test
If lower, replace battery, it has an internal short

If the same battery is OK
Well 12.2v or lower is a failing battery, so replace it as well

Key off and in your pocket, in the cab fuse box pull out Fuse 26, 10amp, puts the GEM to sleep(it stays awake 45-60min after key off doors closed)
Close the doors
Unhook one battery cable and hook amp meter up between that cable end and its battery terminal
Should see 0.03 to 0.07amps, 30 to 70mA
Thats the normal amp draw

If higher pull one fuse at a time in engine fuse box and see if amp draw goes down
Make a note of the number, and put it back in, and go to next fuse

There are several fuses that should draw power with key off
Keyless Entry has to "stay awake" listening for "fobs", lol
Radio needs to keep the time and presets
Computer needs to keep its memory
But these only draw a max of 0.070A, 70mA

 

[Kiyp]

I spent a while unhooking the aftermarket CD changer, which in pretty sure was hooked up to the illumination circuit, and there was a strange wire spliced into the rear light harness going up to one of the tail lights, i disconnected it and it didn't harm the lights ability to function, i checked for any messed up wires around the illumination guage and didn't find anything, the lights seem to stay on no problem now without the fuse being blown

Currently im testing the alleged drain on the battery, it was left not running for a couple days and still ran so i think that will come up clear, and previously ny friend claimed the radio would drain the battery in 40 minutes so he removed the fuse, but im pretty sure removing that really old CD changer system probably fixed that, shouldn't take me long to test that theory, as for if the battery is dead, i highly doubt that tbh mostly just because its a practically brand new battery bought like 6 months ago that has seen hardly any use, in any case if it passes all my tests im going to drive it around all day with the lights on and if the fuse doesn't pop i think I'll call it good, then all thats left is the tps and maf and a/c compressor and i should have a pretty good truck seeing as its only got 66k miles rn