Nissan Repair: 89 240sx electrical problem, 89 240sx, inline fuse


Question
thank you very much for the help.  In fact, i've looked at wrecking yards, for the harness, and it turns out they've all been (at the yards i've checked thus far), in similar states of disrepair (as if their stereos were stolen too, or people in search of such, like me, has beat me to the parts i need).

my question, actually, was more in interest to learn how to address my dash lights not working.  The stereo, i can always hook/wire up peripherally, but I was going to do something similar to make my dash lights work, and my friend stopped me, insisting that i go thru proper channels so that i don't end up causing further problems.

so my question is if there's a "relay" or something inline to the dash light assemblies that i should check.  it's not the fuses (as i mentioned, initially, the fuses would blow, until i had the one fateful "pop" that did something else, and the fuses seem fine ever since, but the lights still don't work).  

so any advice you may be able to provide in how to troubleshoot my dash lights not working would be very helpful.  

my manual (a Chiltons) has very limited diagrams that don't show anything about the dash (only head/stop lights and other components).  The exploded diagram of the dash, to show how to remove it, does not show any wiring/electrical aspects that help me to determine if there are relays or something else, besides the fuse box, to consider.

my intention was to hook up a peripheral wire, with an inline fuse, interrupted with a switch, straight from the battery, to the "dimmer switch" connector, (thus, by passing the switch), but my friend warned me that this could result in a fire or other problems later, if i don't match the appropriate current that it's supposed to have, and/or resistence.  

so i'm trying to find the "correct" way to fix my dash lights (as using my cell phone to illuminate my consul at night is getting old).

thanks again, and happy holidays.

raison


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Followup To
Question -
Hi, first of all, your wealth of knowledge is very impressive, and appreciated.  My issue is this:  some time ago, someone stole my stereo (and so kindly took with them, the wiring harness and all accompanying metal structures surrounding the stereo, and leaving a gaping cavity in my dash)..  while attempting to (very stupidly, i realize) try to find the right wires to re-install a cheapo stereo, i managed to mess up my dash lights.. initially, during my process of elimination of finding the correct wires, i started popping the fuses for the instrument panel.. then, at one point, i heard a louder "pop", and the fuse has been fine ever since (the lights in the dash don't seem to work at all now).  some things do (brights indicator), and other small LED's, but not the normal lights for spedometer, tach, air flowheater control buttons/ac, etc...  even when i remove the stereo, it has no effect.  I can't seem to locate a wiring diagram to show if there are relays or something else that needs to be changed.  

any guidance would be greatly appreciated for this.  I did have a relay go out some time ago (which made my starter not work), and as a "temporary work around" so i could get to work, i had a direct lead from the battery, to the starter, interrupted by a 3 amp switch and an in-line fuse), but since having replaced the starter and the starter relay, that has been working fine (i had suspected that it was the ingnition switch, and hadn't even considered the relay).

my second problem is an irregular idle.  it fluxuates between 1000 rpm, and down to about 600 or so.  not constantly, but seemingly spurratically.  is this timing?  i have an EGR valve on it's way out, but they usually stick "closed", so i didn't think that was it.

thanks again,

Raison
Answer -
The radio question is not your fault since Nissan has some tricky wiring.  Some wires are grounded when the key is off and powered when they are on.  My best advice is to go to a wrecking yard and cut out what you need and replace your harness with them.  That is, cut out enough so you can solder and heat shrink all the wires back the way they were before the bonehead stole your stereo.  Now that you have done that get a install kit and plug the new radio into the factory plug.  On the  idle problem it is either the idle air motor or a dirty throttle body.  The engine needs to know where the idle is to maintain it.  If the throttle is dirty or the idle motor is gummed up or defective it will surge.  Now, a really bad vacuum leak could cause it too so check the PCV valve.

Answer
Rai,

If you disconnected all the wires to the new radio and the lights still do not work on the instruments you should check and see if the resistor that controls the dimming of the instruments is not blown.  Otherwise, you have a burnt wire in the harness that feeds the lights.  You could always wire around it from the headlight switch, where the wires come out under the dash.