# 85' Nissan 720 Pickup Z-24 electrical problem



## steelraj (Aug 23, 2010)

Hi guyz!

I have an 85' Nissan 720 Pickup with a "Z-24" motor. I recently left my key switch on and it drained my battery. I had the battery and Altenator checked and replaced both of them. I started driving it and whenever I would turn the lights or wipers (or both)for an extended period of time the truck will cut off. I replaced the battery and altenator again now I noticed the Horn and tail lights do not work. My inside Dash lights dont work as well. Could a relay be bad? I check the fuses and they are ok. Any help will be appreciated. Tks!
Raj


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## smj999smj (Jan 1, 2006)

Sounds like you have an open fusible link. At or near the positive battery terminal connection will be a fusible link subharness with a green and a black wire. Check the black fusible link wire. This link goes to a white wire, which feeds the following: charging system and fuses #8 through #13 in the fuse block. These include horn, stoplamp, illumination, tailamp and marker llamps, hazard lamps, blower motor, clock, radio and chime.


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## fnstone (Dec 7, 2010)

I have a problem with my running lights/dash lights.
When I turn on my headlights there is a considerable lag time before the dash lights & "parking lights" come on. The problem has gotten worse as the weather has gotten colder, but I don't know for sure if that is a factor.
I tried studying the wiring diagram but haven't found any answers yet.


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## fnstone (Dec 7, 2010)

An update re my running lights:
At least twice now the delay has taken the same amount of time, when on driving home they came on at the same point in my trip.
This evening I timed it and the delay seemed consistent.
Someone suggested to me that it might be a loose connection but it doesn't seem like any loose connection I have dealt with before, but rather a relay going bad.
I'm using a Haynes manual & having a little trouble tracing the wiring diagram but I think the "bulb check relay" might be part of the circuit.
The book says nothing about this component, does anyone know where it is located and what it is for?


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## Ben1 (Nov 12, 2010)

fnstone: Sounds like your headlight relay is going out. I think it's under the dashboard on the driver side. Turn the lights on and off and you can hear/feel it click, that should help you locate it. The relay has a physical switch that opens and closes inside, that would explain why the cold temp. is affecting it.


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## fnstone (Dec 7, 2010)

That was my first guess and I bought a new one ($35!) but it didn't help.

I took the cover off the steering column & will start testing circuits next. I'm starting to think that maybe the switch is gummed up. 
If I don't get voltage to the circuit coming out of it I thought I might try spraying some contact cleaner in it before I shell out for a new unit. 

The Haynes manual shows the headlight relay as the front most unit mounted over the fuse box with the heater relay behind it.


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## fnstone (Dec 7, 2010)

Looks like I fixed the problem. 
the switch isn't sealed so I was able to spray some plastic-safe contact cleaner in there and it seems to be working fine now.

I have another question re the dome light. It comes on when the door switch is activated but if there's a manual switch for it I haven't found one. 
I'd guess that the dash light dimmer might be meant to turn it on but it doesn't.
While I have the steering column cover off I thought I'd mount a switch on it but I'm having trouble identifying the dome light circuit under the dashboard.
Does anyone know what the wires look like?


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## A-10 (Dec 14, 2010)

*Tail light / dashlights delay*

I've been having the same problem with my '84 720 pickup. In the summer the tail lights take about 15 seconds to turn on after the headlights come on. However, in the winter it often takes 15 to 20 minutes for the tail lights and dash lights to come on after the headlights. The colder the temperature the longer the delay. I'm going to try your solution.

BTW the dome light switch is on the dome light fixture in my truck and the holding relay is under the passenger seat.


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## fnstone (Dec 7, 2010)

Last night was in the 20's and I still had some delay but it had improved. I suppose it may take a few more doses.

The way the wiring diagram is drawn it does look like the dome light switch is on the unit. I don't know why I didn't look there in the first place.


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## fnstone (Dec 7, 2010)

The contact cleaner seems to have done the trick.

I had another problem which seemed to have been electrical, but which caused the throttle to stick wide open on acceleration and which I seem to have fixed, but I don't understand why.

When I looked under the air cleaner I saw where the ground wire(?) from the throttle valve switch had come loose from a repair done by a previous owner. I soldered it, so that I didn't have to remove the carb.
There is also an electrical terminal at the base of the carb on the outboard side of it which was very dirty & maybe loose (I'm not sure). I cleaned that too and now I can accelerate without the throttle sticking open.


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## ortech69 (Apr 6, 2015)

*tail lights*

hello,i have a 83 nissan 720 pickup ,,my problem is that in the am when i turn on my headlights i have to wait 5 to 6 mins for my dash and tail lights to turn on .. any ideas what could be the problem ? thanks in advance


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## smj999smj (Jan 1, 2006)

You could have dirty contacts inside your light switch. You would have to test the switch and check input/output to confirm. If so, you might be able to take the switch apart and clean the contacts, but given the age, a new switch might make better sense.


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