s13 digital speedometer issue(not what you think it is, already tried the cap fix)

[wrxkyle]

so i just did the capacitor fix Technical Articles: How to: Repair 240sx digital speedometer with HUD. (http://www.nicoclub.com/articles.php?id=158878)) and i still don't get the speedometer or the HUD to light up at all. i did this to two different clusters i have for the car, and no dice on either of them. what else could it be? all the rest of the gauges including the tach/fuel/warning lights/and i'm pretty sure even the odo works.

i'm going to check the yellow-green(VSS) wire for continuity all the way back to the ecu, but are there any plugs that might be unplugged that would cause this? dash lights dont turn on either, though when you turn on the ignition with the headlights on the ashtray light comes on.

i just bought the car, i now have the dash completly out looking for this problem, any help here? got the car 3 days ago lol, way to jump into modding eh?

[wrxkyle]

is there any way to eliminate other possibilities, i think the vss module with the gear on the end of it in the transmission was replaced recently, so that should work, is it possible i just have two completly dead clusters? from studying the wiring diagrams i can't figure out what might be bad.

anyone have an extra digital cluster that is working that i could test with(in the utah provo/salt lake area) or a 240 wired for digi cluster and hud that i could plug one of my modules into and check to see if it's just plain dead?

<Update>
so i have the dash out, no connectors for the hazards or any other switches, and after driving around fairly hard for about an hour i tuned my lights off and then back on and wtf, the speedo lights up and is working, but the dash lights are still off, tach isn't lit but still works, and after a bit the speedo goes blank again, turnign on and off the lights turns it back on, i'm stumped, could it be i got some bad replacement capacitors? or maybe i just did a really bad solder job?(i have experience soldering little things though :( )
could it be something to do with a lighting module? is there even one in these cars?

any help would be greatly appreciated

[wrxkyle]

update, tcu burnout.

i saw somewhere that if your radio harness is cut it probably shorted the tcs, which mine is, and my tcu had the fried trace so i soldered a wire over that and it would probably be all fixed now but i resoldered the speedometer(thinking that was the problem) and now it doesn't light up, not sure if something on the speedo board is fried or if the tcu is dead now. i could REALLY use some help on finding a tcu and a working speedo cluster to see which it is. i can't find any 240 at junkyards here. :rant2:

[wrxkyle]

bumpity, could use some help here, what else can burn out in the lighting illum line that would take out the speedo and intrument lighting but not the TACH and other gauges, is there anything?

[sil80_88]

dead bulbs? haha could be something as simple as that

[wrxkyle]

dead bulbs? haha could be something as simple as that

oops sorry, meant to say tach, the speedo doesn't light up.

[wrxkyle]

so, i guess it helps if the radio fuse is in, but all in all i figured that one speedometer was probably fine before i messed with it, and the other had the power out, the good one i ruined soldering, but luckily the power supply on the back is detachable and i swapped those and now the speedo lights up, didn't bother to check the dash lights as i was so happy the speedo and hud worked, hopefully this will be helpful to all of you, also i did have to solder the tcu. now just to put the whole dash back together.

[bigdodd]

had the same problem with my 240...replaced the cap, and still nothing. had the gauge assembly disassembled and plugged it into the harness, moved the circuit board that i soldered the cap to,(with the key on and lights on) and when i moved it the dash lights came on. apon closer inspection found bad solder connections where this board attaches to the main board. Still havent got the speedo to light up tho >.<

[wrxkyle]

yah you do have to be carefull about the mounting pins at the base of the board, i had to redo those. now the speedo works but the dash lights do nothing. i'm pretty sure they aren't all burned out, but the clock light does come on when the headlights are off, what could it be? speedo and hud now work perfectly, the hud dimms with the dimmer switch too so that should be good, and i'm pretty sure the tcu is good as well, but have no way to check(i already soldered the burnt out jumper.

[nuS13]

are the tcu's different from the hud speedo to the analog one?

[gsmith358]

Well I have an issue with mine as well. I had nothing till I found a ground wire that was broken on the HUD wire harness. If you trace the three plugs back and find the white and black chase harness, the grounds for the HUD unit comes from the black connector. That was the issue with the temp and Fuel. The speedo was working when I first plugged the unit in. Now everything but the speedo will work. I am lost. Almost looks like it has no power to tun the digital speedo on, yet I checked, it has voltage.

Replaced Dimmer switch and tested it. no change.
Replaced TCU, no change.

[IMSLIDIN]

sorry to mess with such an old thread but im trying to figure out my digital cluster now i got a 1989 240sx and got a digi cluster from a 1991 i think so doch i swapped over the tach for the one that was already in my cluster...i used the back of the soch tach then the face of the digi and it works fine now i have no dash lights...tail lights work tho the speedometer would come on then go off a couple seconds later but it would fade away so i read that diy on fixing it where do i find a capacitor that will work so i can swap them out? and any ideas?

[Vatche]

i have these same problems with 3 digi clusters. i have taken all 3 apart with no luck trying to fix them. i have a 4th good cluster from my coupe and that works just fine in both cars that i tried the bad ones in. i also tried many different tcus dimmer switches and extra grounds. fail.

[IMSLIDIN]

well from what ive heard the digi clusters are hard to find working but i think im gonna try to find another cluster i like to put in and i was gonna do a doch swap so ill do all the wiring myself......thats gonna suck but itll be worth it

[Likstreetracing]

I have a 91 240sx the hud and speedometer backlights dont turn on, the clock light turns off after I turn on the headlights.I replaced the cap on the speedometer on 3 different ones and it still does not work. I replaced the tcm and still does not work. The dimmer switch works because I can see the lights dimming on the a/c lights. What else should I look for. I checked all fuses and they are all good.

[Sstrappjr]

finished the capacitor fix. No bueno. Still no speedo. Guess next is chasing the wire bundles and the TCU?

[Vatche]

just for future reference, the actual digital speedometer unit can have a bad circuit that stops the cluster from illuminating(even if the speedo comes on) what I did on one cluster like that was grounding the red wire that comes out of the digital speedometer, and screws to the back of the plastic gauge cluster circuit board.

Also replacing the capacitor is not the only problem with the digital speedometers. I have found some bad power supplies, and some that I still have not figured out.