1970-Bronze

Ok, I checked and I'm not getting any voltage at the connector at the transmission or at the switch under the dash.

I looked at the AIM but could not find the circuit.

Where does the Th400 kickdown tie in to for voltage? Which fuse?

Thanks,

Tim

goinbroke

Not sure if this is going to help or not. I'm looking at a 74 service manual diagram and it looks like power is fed by a brown 12 gauge wire from the ignition switch to the fuse panel. The brown wire leads to the 25 amp "wiper" fuse. This would be the lower left fuse on the 74 fuse panel.

1970-Bronze

Hum...Ok. The wires at the switch by the petal are orange and black. So, does the diagram show where either of these wires connect?

Thanks,

Tim

goinbroke

It looks like both wires from the kickdown switch go through the dash to the engine compartment. The orange wire goes to the trans solenoid. The 16 gauge tan wire goes to the engine side (back) of the fuse panel. Once that wire goes through the 25 amp fuse it becomes the 12 gauge brown that travels to the ignition switch.
On the 74 diagram the orange wire is circuit 55 (kickdown on auto trans). The tan wire is on circuit 141 (feed ign. switch Accsy. Controlled fused). The brown wire to the ignition switch is circuit 4 and is also named feed ign. switch Accsy. Controlled fused

1970-Bronze

Ok, I have gone over the AIM manual for my 1970 so many times - my head hurts.

None of the circuits are numbered in my manual (or match what your saying) and the kickdown is not shown anywhere (at least that I could find). It looks like the schematic was based on the manual transmission and not the automatic.

I have both orange and black conductors at the switch and the transmission - but no voltage. It has to be connected somewhere to pick up the necessary voltage but I can not find it.

I hate to be a BUBBA but do I just pick up 12V (install a fuse) and tie it in?

Thanks,

Tim

goinbroke

Tim, If I'm reading the diagram correctly, the voltage comes from the ignition switch on top of the steering column.
I'm on my way out the door heading for Dallas to have a kidney stone removed. Hopefully this evening (if I'm still alive) I can get some time to look at this closer.
In the mean time this will bump you to the top so that maybe soneone with some hands on experience can help.

1970-Bronze

Ouch, a kidney stone - I hope your feeling better soon.

I'm going to dig into it again tomorrow.

TimAT

I just looked at GM wiring diagrams from 1969 to 1973. Not one shows the circuit for the THM400 kickdown. Now that's just plain goofy.

...Roger...

The power comes from the AC/TCS fuse( upper right in the fuse box)and goes to the pedal switch and then to the trans.

goinbroke

Thanks, It's actually a bladder stone. Doc tried to remove it today using a tool that they put up into the bladder, but the stone was too big to pull through..... talk about bringing tears to your eyes. I'm scheduled for out patient surgery Tuesday a big Baylor.

Tomorrow I'm going to try to fire up my scanner and post the diagram from the manual. This will be from a 74 so can't say for sure your 70 will be exactly the same, but I would think they would be very similar.

Peterbuilt

You'll be fine! My friend went thru the same thing about a year ago and was up and about and felt 100% in no time.

1970 Bronze You might find a better schematic here: http://www.nrjvette.com/johdotukset/?c=d;o=d

PG.

1970-Bronze

Yes, it is better but the switch isn't there...unless I missed it.

1970-Bronze

Well, that would explain why I can't find it.....

...Roger...

That is correct.

...Roger...

Your not going to have voltage at the trans until the gas pedal switch has been tripped and now that you only have one terminal on your trans you should only need to use the orange wire.

goinbroke

Tim, see if this is any help. Some of it is a little blurry. If you have any trouble reading any of it let me know. Remember that the 74 also has the hood air door solenoid activated from the kickdown switch. Wiring could be somewhat different because of that.
Hope this helps.

...Roger...

Goinbroke that diagram is wrong for a 70. The wire positions in the bulkhead are wrong,wire color is wrong and fuse position is wrong , but all the components are there. The basics are there and its a simple circuit so it shouldn't be to tough to figure out.

1970-Bronze

Ok, success.......or at least so far....

I now have voltage at the kick down switch. The AC fuse was blown and that's where the voltage comes from. I replaced the fuse and now I have voltage (at the switch).

So for reference it is the most upper right hand fuse (AC/TCS) - thanks Roger.

Now to check the trans. I couldn't hear the solenoid when working the switch.

Unfortunately, it's raining here and I won't be able to drive test it today.

Thanks guys - I'm getting closer.

Tim

goinbroke

Sounds like you have it going your way Tim. Sorry if I led you on a wild goose chase.
Rain here too and we have sure needed it.

1970-Bronze

goingbroke - actually you were helpful. It's all good.


Now.....for some more fun. The connector at the trans is a two conductor ( one female socket verticle and one female socket horizontal) and the trans only has a single blade - horizontal.

For some reason, the voltage is on the wrong socket so it doesn't work.

Thoughts?


The way I see it.....

Option 1 - make a jumper wire and tape it up to maintain the harness. Still sorta bubba.....

Option II - cut the connector off and swap the wires and resolder. May prove troublesome for a future owner or me if I forget. Probably very bubba.....

Option III - get a new switch for the trans......that's a lot of work for the solution since you have to drop the pan to install.


Why is it never easy.......

Tim