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720 starter relay?


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There is no starter relay as such. Power from the battery is sent to the starter solenoid when the key is in the start position. The starter solenoid connects the battery power to the starter windings and also moves the starter gear out to contact the flywheel starter ring gear.



Poor starter response could simply be a bad connection. Before replacing anything spend some time and make sure the problem isn't something simple to fix.


First clean both the battery terminals and cable ends and make sure they are tightly bolted on. Make sure that the starter bolts are tight so that it is properly grounded. Clean and tighten the positive battery cable where it connects to the starter terminal. Also clean the negative battery cable where it is bolted to the intake.


If there is still a cranking problem it could be a tired battery (or it isn't being charged properly) or the starter is bad.

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Not trying to be smart just trying to figure this out. So sorry if i sound like i am because i am not. I really do appreciate the help you get here.


I know what you are talking about. But comming off the ignition switch the power goes through a relay before it goes to the selonoid where it is connected by a spade connector. The relay it runs through is pulled in by the clutch pedal switch according to the wiring diagram. The power that runs through the normally open clutch pedal switch also comes off the connector to this relay. On my last truck an 81 720 I ran a hot wire fused off the battery through a switch and connected it with a spade connector to the starter selonoid. and it worked every time from then on and just used the switch to turn on and off not start. This 84 is in a lot better shape and i just asume not start rigging things like that. The clutch pedal switch ohms out good all the time. There is a drawing on page 13-21 of my haynes manual that calls it an interlock relay. I am not against bypassing a saftey interlock since it is my truck but do not want to mess things up ifin i do not have to.

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You may be reading it wrong. The only relay in the starter circuit is used on automatic equipped models to prevent starting in reverse or drive. On standards, power to the starter solenoid comes directly from the ignition switch.


There is a clutch switch for the fuel shut off system on the '84s.



So what is your truck doing anyway? Turn the key and nothing happens sometimes?

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Yes that is what the problem is. I can turn the key and 2 out of five times it does not even try to start. It is not cause of a loose connection in the way that you descibed in your first post. I just took the starter off of one truck and swapped to the other all the connections are tight and a good ground. On the 81 I had this same problem until i made a switch like i said in the second reply. On one of the other prints i see the fuel cut off selonoid but do not really see how it is wired in. It would not be a problem though in the start curcuit. But the print in the book also does not show from what year to year the diagram is for. When I turn the key it goes through just like when it starts but does nothing. On the 84 it has an electric fuel pump you can hear run until it builds up preasure if it is quiet with the radio off. With just pumping the pedal a time or two you hear the fuel pump come back on. As long as the key is in the run or start you should have power to the fuel pump.

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Likely the ignition switch. You could remove the solenoid wire (Black/Red) and connect a volt meter to it. Have someone turn the ign. on, off, on, off while watching that the meter reads power on and off. If the key is on and no voltage at the solenoid wire... there's your problem.

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I will look further in a week or so. I hit a deer on the way to work so to repair it will come before an intermentant (sp) starting problem. I did find out though that on a 84 the grill is taller so you must change the metal part below it when you swap in a 81 datsun grill into an 84 nissan. Will have to live with a bent bumper though since my parts 81 had a bent one to. Both the blinker on the front must be swapped with the other pieces also. But still not a bad swap. The only thing that saved the radiator was the ac condensor coil. It needed freon anyway and i do not usually us ac anyway. If i did both my trucks were ac trucks but not going to mess with it. I finally got this 84 running as well as the 81 did so i really would like to drive it more. I was wondering if the intake between a 2.2 and a 2.4 would swap. It looks as if it would but you would also think the carb bolt pattern would be the same too but it is not. Anyway i have far better luck with nissan/datsun stuff than toyota not that one is better than the other just some people have better luck. Thanks for the help.

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