Logic Box

[exarkun1178]

The last hanging chat on my restoration is the logic box.  How hard is the job?  The shop doing the work doesnt really want to do it.  maybe that they are sick of looking at the car?  anyways.  ordered it from Ray today.

[jbcollier]

It's not "hard" at all: you just hook it up as outlined in the wiring diagram.

[EuropaTC]

errr, what's a "logic box" ?

Brian

(struggling to find anything like "logic" in a 60s Lotus      )

[ron parola]

"logic box" controls seat belt light or buzzer on federal cars, something that you guys luckily missed out on. Better yet if you had an MGB it had a diode from it's box to the ebrake lever. WHEN not IF the diode  failed (shorted not open) then, with the ignition on, you pulled up on the ebrake the starter would motor along, sometimes starting the car.... guess how I know! Cheers rp

[EuropaTC]

WHEN not IF the diode  failed (shorted not open) then, with the ignition on, you pulled up on the ebrake the starter would motor along, sometimes starting the car.... guess how I know!

Park brake starting the engine       in the words of Mr Spock, "that is NOT logical"......   

Thanks for the info Ron, it sounds like an excellent opportunity to "add some more lightness".....

Brian

[blasterdad]

I've added a lot of "lightness" over the years... Still regret not unhooking the one in my F150 while I replaced the heater core.  Damn thing drives me nuts!

[exarkun1178]

Update

Turns out th elogic box was both cheap ($150) and not to bad replacing (~1 hour)  For the first time since 1989 all the lights work!

[BDA]

That HAS to feel good! Small pain in your wallet and all the lights working! Just don't tell the ghost of Joseph Lucas!

[EuropaTC]

    

All the lights working ?

On the same day ? 

On a British car and a Lotus one at that ? 

oh dear, this isn't going to end well my good man.    You're going against Nature and years of tradition now......  is that smoke I can smell ?
 


Brian

[exarkun1178]

I agree im likely at the high spot in the cars life. 

[blasterdad]

Is the "logic box" just for the seat belt system as ron parola stated, or does it do other things as well?...

[exarkun1178]

The logic box in the S2 controls the turn signal lights, break lights and running lights.  Unlikely my car has a seat belt sensor. 

[blasterdad]

The logic box in the S2 controls the turn signal lights, break lights and running lights.  Unlikely my car has a seat belt sensor.

Thanks for the info, havn't tried any of my lights yet, but good to know when I do.

[Roger]

There's a difference between the DB10 relay for brake and indicator lights and the logic box used in late TCS for seat belt, warning etc.
Don't confuse them. I'm pretty sure the S2 doesn't have a logic box, and I built my own DB10 for about $15.

[4129R]

I am now finishing the wiring for 3755R which conforms to the later circuit diagram, so the starting number of 3924 is incorrect.

Does anyone actually know what the "logic box" is for?

Is it just about 12 open female terminals in a circular connector, or is anything actually plugged in to it, which I am missing.

I just cannot work out how the starter relay ever worked, as according to the wiring diagram, there is no direct connection from the ignition switch in start mode, via the white and red wire, to the starter relay,which triggers the starter solenoid.

Alex in Norfolk, the home of Lotus.