1978 200SX- No power to dash

[Lewie]

hey all- 

long time lurker, first time poster. Recently finished rebuilding the engine in my '78 200sx, and to my dismay the dash has no power-no tach, speedo, radio, horn, lights, buzzers, taillights, etc. Nothing works except the starter. Fuel pump doesn't switch on, we had to start the car (and it only ran for 5 ish seconds) by pouring fuel into carb before starting. Don't understand why the car is doing this. We had power in it before we removed the engine. Any body have any ideas? I'm at a loss as to what it could be. Checked all the fuses (visual inspection and continuity test w/ multimeter) they were fine, tested the fusebox with the accessory switched on-no power. Any help would be greatly appreciated, I'm running out of time to get this done and am at wit's end. 

[datzenmike]

The speedometer is mechanical isn't it? Should work without power. Same with the fuel pump, it's mechanical on the S10.

 

If no tail lights the dash and headlights probably don't work also

 

 

I assume you took the battery out for the engine removal? certainly you must have disconnected it. The positive cable goes to the starter but there is also a wire from the positive terminal over to the right fender? Probably to a plastic box? inside are the fusible inks of which (probably) there is one for the ignition switch which also sends some power the the fuse box for accessories that need to be switched such as wipers, heater radio... one for the lights.... one for the fuse box for things that are powered all the time like interior lights, clock, horn.

 

 Funny that there is ignition power for the coil and the start signal.

 

 

[banzai510(hainz)]

start at starter lug then work your way up with volt ohm meter.

 

Clean fuse box, replace fuses

[Lewie]

Worked on finding it, no luck. All wires in the ignition switch are good (12V for the main ignition, all of them read 12V when car switched on) I’m out of ideas. @datzenmike I found the black box, but it had two small metal boxes with plugs running out of them. I have no idea what to do. @banzai510(hainz) fuse box is clean, fuses are all good. Expect one of them is larger than the others, and slides upwards into a whole rather than clip into place. It doesn’t seem to fit properly. Will get a pic tomorrow. Other than that, all fuses are good. No idea why power isn’t getting to fusebox. Power is reaching ignition switch, and all the wires in the switch. 

[datzenmike]

One of the wires from the ignition  powers a few fuses in the fuse box. Wiper and washer, heater fan, radio, gauges and instruments. don't have a factory service manual for the S10 

[banzai510(hainz)]

On 5/7/2024 at 7:36 PM, Lewie said:

horn, lights, buzzers, taillights,

this should have power with out the key switched.

power to thefuse box then check for power after the box to the circut it goes to.

 

 

[Lewie]

56 minutes ago, banzai510(hainz) said:

this should have power with out the key switched.

power to thefuse box then check for power after the box to the circut it goes to.

 

 

No power with the key on. With the key on, there is no power to the fusebox. Can’t figure out why

[Lewie]

10 hours ago, datzenmike said:

One of the wires from the ignition  powers a few fuses in the fuse box. Wiper and washer, heater fan, radio, gauges and instruments. don't have a factory service manual for the S10 

Ok. I’ll see if I can trace that wire to fusebox. Tricky to do with dashboard still in place. 

[EDM620]

Got a ground cable to the chassis? You should run 2 grounds, 1 to the block & 1 to the chassis/body. Electricity needs a complete circuit to function. Quick test with Ohmmeter from neg terminal on battery to block & test to body.

[Lewie]

1 hour ago, EDM620 said:

Got a ground cable to the chassis? You should run 2 grounds, 1 to the block & 1 to the chassis/body. Electricity needs a complete circuit to function. Quick test with Ohmmeter from neg terminal on battery to block & test to body.

Yep, fender+engine block grounds. Car starts, but electricity isn’t getting to fuse box. Going to try piggybacking

[banzai510(hainz)]

2 hours ago, Lewie said:

No power with the key on. With the key on, there is no power to the fusebox

Not True.

your brake lights, dome light and headlights will all come ON  with out a key and OFF position. so those circuts are hooked up to the battery via the lug on the starter fuasable link wire to the fusebox. Ignitions and certain items use the key switch, Radio, fan turn signals bla bla bla.

[Lewie]

22 minutes ago, banzai510(hainz) said:

Not True.

your brake lights, dome light and headlights will all come ON  with out a key and OFF position. so those circuts are hooked up to the battery via the lug on the starter fuasable link wire to the fusebox. Ignitions and certain items use the key switch, Radio, fan turn signals bla bla bla.

um....no. I have no brake/headlights. I mashed the brakes, friend stood behind the car. Nothing. Only electrical things working at the moment is starter, ignition switch and ignition coil. 

[datzenmike]

If power to the ignition (usually a thicker White/Red stripe) then when on it should also feed a switched power to some of the fuses in the fuse box. Check ignition switch for an output turned on by the switch.

 

Check both sides of all fuses with the ignition on. Check the clips not the actual fuse it may not be making good contact

 

Headlights are wired directly to fuse in the fuse box but goes through a fusible link. Again check for power on the clip not the fuse body.

[banzai510(hainz)]

weid.

Im not a 200sx expert but weird how you got ignition and starter power. but no lights, brake light

 

 

i usually wiggle the fuse. example put the headlamps to ON and fuck with the fuse box.

 

Usually with head lamps(OFF mode) if you have a test light ground the one end and put the pointy end on the 3 prongs. they should have 12v (the test light will light up) means the power is feeding to the 3 prong lamp. then when you switch to ON one propng will go to ground which lamp will be off

[datzenmike]

Head lights don't go through the ignition, they are on their own fusible link.

 

Heater, radio, wiper and washers, dash instruments (gauges) and oil, brake and charge lamps go through ignition.

[Lewie]

2 hours ago, datzenmike said:

Head lights don't go through the ignition, they are on their own fusible link.

 

Heater, radio, wiper and washers, dash instruments (gauges) and oil, brake and charge lamps go through ignition.

Well, none are working🙃. No electrical stuff at all, aside from ignition. Ended up just piggybacking the fuel pump today, got the car to fire up no problem. Touched around the fuse box a bit, managed to get my ‘fasten seat belt’ light to pop up

[Lewie]

5 hours ago, datzenmike said:

If power to the ignition (usually a thicker White/Red stripe) then when on it should also feed a switched power to some of the fuses in the fuse box. Check ignition switch for an output turned on by the switch.

 

Check both sides of all fuses with the ignition on. Check the clips not the actual fuse it may not be making good contact

 

Headlights are wired directly to fuse in the fuse box but goes through a fusible link. Again check for power on the clip not the fuse body.

I found a switch under the dashboard, flipping it did nothing🫤wire from fuel pump+another black wire (not sure where it went) ran to it

[banzai510(hainz)]

did you check if headlamps had 12volts on the 3 prongs with the switch off???????????????? 

 

i cant help if you dont ck this. This is a simple check.

[Lewie]

@banzai510(hainz) yep, checked. And no power, nothing going to the head

[datzenmike]

On 5/9/2024 at 4:01 PM, Lewie said:

I found a switch under the dashboard, flipping it did nothing🫤wire from fuel pump+another black wire (not sure where it went) ran to it

 

S10s don't normally have electric fuel pumps but if you put one in good to have an anti theft switch that keeps it shut off.

[datzenmike]

Find the ignition switch. There should be a White wire with Red stripe. This should have 12v battery on it DOES IT????

 

1/  If NO go out to the battery positive terminal. It should have a thick cable down to the starter and a smaller one probably going over to the right side inner fender. Probably to a black plastic box. Take the cover off and find where the smaller wire from the battery goes. It should have two GREEN fusible links.

 

One of the GREEN fusible links is connected to the White/Red strip wire to the ignition. Follow the 12v from the battery to the fusible links and to the White/Red wire. Problem has to be here, likely the fusible link.

 

The second GREEN fusible link goes to the fuse box and powers the headlights through the headlight switch. Check both sides of the fusible link for 12v.

   

 

 

 

[banzai510(hainz)]

So headlamps have no power

this come from as Mike stated from the batter cable to the starter lug up tp fuse box then to the lamps.

 

get meter or test lamp and probe from batter and follow up to fuse at least one side of the fuse should have 12volts if not then its inbetween there

 

Im thinking since so many circuts are not powered this is a simple fix

[Lewie]

On 5/13/2024 at 1:18 PM, datzenmike said:

Find the ignition switch. There should be a White wire with Red stripe. This should have 12v battery on it DOES IT????

 

1/  If NO go out to the battery positive terminal. It should have a thick cable down to the starter and a smaller one probably going over to the right side inner fender. Probably to a black plastic box. Take the cover off and find where the smaller wire from the battery goes. It should have two GREEN fusible links.

 

One of the GREEN fusible links is connected to the White/Red strip wire to the ignition. Follow the 12v from the battery to the fusible links and to the White/Red wire. Problem has to be here, likely the fusible link.

 

The second GREEN fusible link goes to the fuse box and powers the headlights through the headlight switch. Check both sides of the fusible link for 12v.

   

 

 

 

Found it, it works. 12V reading. Still no power to dash

[datzenmike]

Found what? What works? Lots of ideas where are you on that?

[banzai510(hainz)]

I like that .Found what?