1995 Toyota 4Runner dash lights out

Tiny
THEBLUEROBOT
  • MEMBER
  • 1995 TOYOTA 4RUNNER
  • 3.0L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
My dash lights are out I must have bought it like that here are the details

Good fuse

Turn signal and engine lights show on dash just none of the instruments

Previous owner installed big ass stereo

Ive tried bypassing the dimmer switch but I may be doing it wrong, the fuse blows everytime I do.

Here is a picture
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Monday, November 16th, 2015 AT 11:10 AM

7 Replies

Tiny
CARADIODOC
  • EXPERT
First check if the tail lights are working. Next, check the other interior lights like for the cigarette lighter, shift indicator, rear window defroster switch, and things like that.
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Monday, November 16th, 2015 AT 12:36 PM
Tiny
THEBLUEROBOT
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All that works fine. Its just the dash. Obviously you would know that if you read my post, because how else would there be fuses blowing?
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Monday, November 16th, 2015 AT 1:06 PM
Tiny
CARADIODOC
  • EXPERT
My my. Is that the attitude you show everyone who is trying to help you? Obviously you have no idea what you're doing in the circuit by jumping a hot wire to a ground wire.

The dash light circuit is part of the rest of the lights that illuminate a lot more than the dash lights, and all of those interior lights feed off the tail light circuit. Knowing which parts of that circuit works and which parts don't will get me into the right part of the wiring diagram, but apparently you feel that information is top secret or worthy of a sarcastic reply. You're going to have to find a mechanic who can look for himself to get all the information he possibly can so he can diagnose the cause of the problem as quickly and efficiently as possible. You'll be paying for his services by the hour, so don't tell him anything when he dares to ask a question. Let him take his time finding out on his own.

"How else would there be fuses blowing?" I could share a dozen ways the 15 amp tail light fuse would blow, however, if your "good" fuse doesn't blow until you stick the jumper wire in the plug, I would think it would be somewhat obvious as to the cause.

If you search enough of my other hundreds of replies where I helped people solve blowing fuse problems, you'll read that I have a trick to allow you to work in the circuit with it powered up, and not go through a box of fuses. That really shouldn't be necessary though if you bypass the electronic rheostat properly. There are some other simple and quick observations that would help me narrow done the location of the problem, but I'm busy with a half dozen appreciative people, and I really need to get back to those conversations.
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Monday, November 16th, 2015 AT 2:17 PM
Tiny
THEBLUEROBOT
  • MEMBER
I'm sorry that was just a knee jerk reaction I had in light of how much non-help I have been getting. I've already posted on several websites and up until now answers have been extremely vague. So far you have written the most. Anyway I don't undervalue your time and I'm sorry I came off sarcastically.
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Monday, November 16th, 2015 AT 2:49 PM
Tiny
CARADIODOC
  • EXPERT
All is forgiven. Now lets fix this puppy!

The glove box light also is fed from this circuit, but it is not controlled by the dimmer. If that light works, that takes care of the positive side of the circuit. The 12 volts comes from the tail lamp relay, so according to my diagram, you won't have a glove box light unless the running / tail lights are turned on.

The rheostat is an electronic module, but it still can be bypassed. We just need the right wire. You should have a green wire. That's the 12 volts that comes from the tail lamp relay. The white / black wire is the ground wire. The white / green is the ground wire for the lamps, but it goes through the dimmer module first on its way to ground. If you want to bypass the module to see if everything else works, either connect the white / black wire to the white / green wire, or just use a jumper wire to ground the white / green to the body.

If the lights turn on, the dimmer module must be replaced, but be sure that 12 volts is there on the green wire. It won't work if that's missing.

If you had found that 12 volt wire previously, what may have confused the issue is the dimmer is in the ground side of the circuit, not in the positive side like they used to do. The fact there's a 12 volt wire adds to the misery.

If the fuse blows when you ground the white / green wire, one of the bulbs, (sockets) is shorted, and logic would dictate it's related to the radio that was in there. The original radio most likely had two lamp wires. One was hooked to the tail lights to make the display dim. The second one was hooked to the dash light circuit to tell the display how much to dim. If someone reconnected those wires incorrectly, it is possible the tail lamp / dash lamp 12 volt supply got connected to the ground side of the lamps. That short may not cause the fuse to blow with the dimmer in the circuit, but it would if it was bypassed. This is a good suspect if the previous owner hacked off the radio's plug and spliced in the new wires. If an adapter harness was used, it's doubtful removing it is causing this problem.

One more tidbit of value. If the previous owner spliced wires for the radio, and sealed them with electrical tape, that can unravel into a gooey mess on a hot day. The dash is made of plastic, but if a bare wire touches the case of the radio, that is grounded, and a bare wire will be grounded if they touch.

To back up for a minute, with the dimmer still unplugged, and with the lights turned on, you should measure 12 volts on the white / green wire too. If you have that, nothing on that line can be grounded or open. At that point everything points to the dimmer module.
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Monday, November 16th, 2015 AT 3:53 PM
Tiny
THEBLUEROBOT
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Alright thank you so much for your help thus far you have been very generous.
I tested the green-white and grounded off and was able to get 12+ volts.
So, deducing from your info I bought the $15 dollar switch. And, it still doesn't work!
What further testing can I do or is it most likely the radio thing you mentioned before?
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Thursday, November 19th, 2015 AT 1:44 PM
Tiny
CARADIODOC
  • EXPERT
Was that the dimmer rheostat or the head light switch you replaced?

If you grounded the green / white wire, and the tail light or head light switch was turned on, the dash lights should have been full brightness. If they did not turn on, stop me right there and let me know, otherwise I'll continue with my train of thought.

Once again, check if the glove box light works when the tail lights are on. If it does, that eliminates half of the circuitry and we have to look somewhere else. All of the following are done with the head light / tail lights turned on. Measure the voltage on the green wire at the dimmer rheostat. You should find 12 volts there. Now measure on the white / black. You should find 0 volts. If you find anything other than 0 volts, there's a break in that ground wire. That break can keep the glove box light from working too.

If everything seems okay up to this point, pick one of the dead lights that's easiest to get to and measure the voltage on the two terminals. One must have 12 volts. The other likely will have 12 volts too due to being not turned on, but once we get this fixed, the second terminal will have 0 volts.

Hopefully somewhere there you'll find the wrong voltage to tell us where to go next. I'll be back in two days to see how you're doing.
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Thursday, November 19th, 2015 AT 7:19 PM

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