1984 720 Steering Column and Plugs - What does this go too?

[bluexl]

Can anyone tell what this plug is spposed to connect too? It is part of the wiring loom that connects to the turn signal and the back of the steering wheel. I am in the process of troubleshooting my hazard lights not working (other post), but when I removed the steering colums  cover I saw this plug not conncted to anything.

 

 

 

 

 

Thanks.

[datzenmike]

That's the plug for the variable wiper delay. The stalk that the wiper switch is on has a twist variable resistance on the end to set the amount of delay. Most just have a built in delay of a few seconds.

[livemeyer]

46 minutes ago, datzenmike said:

That's the plug for the variable wiper delay. The stalk that the wiper switch is on has a twist variable resistance on the end to set the amount of delay. Most just have a built in delay of a few seconds.

Hey Datzenmike, I just swapped my turn signal/wiper controller over to the one with the variable resistance for intermittent wipers and I plugged this link in, but I get no intermittent wipers.  Is there something else I need for this upgrade?

[datzenmike]

If only it were that simple. That's because you need the variable wiper amplifier that goes with it. It's located under the dash on the right side of the steering column.

[bluexl]

51 minutes ago, datzenmike said:

That's the plug for the variable wiper delay. The stalk that the wiper switch is on has a twist variable resistance on the end to set the amount of delay. Most just have a built in delay of a few seconds.

So, there SHOULD be something plugged in to it, or is that only for a model that came with that option? Sorry if that is a stupid question, just wonder if there is a scenario where this plug is left s is with nothing pluged to it.

 

Thank you for the help.

[livemeyer]

20 minutes ago, datzenmike said:

If only it were that simple. That's because you need the variable wiper amplifier that goes with it. It's located under the dash on the right side of the steering column.

Cool.  Thought so.  I'm going to picking apart a 720 I found and now I know where to look for that amplifier part.  I haven't been on this forum much recently because I've spent the past few years building my '51 Chevy 5-window.  But it's been in a shop since February for a new transmission (they're reeeealllly slow) so I've been turning my attention back to my '85, Lil' Blue.

[livemeyer]

So I did a google image search for this amplifier part, it looks like it has a 5-pin connector, would the wiring already be there in a truck without this option?  Just wondering if it's a plug n play situation or if I'm going to have to dig up a wiring diagram before cutting some wires.  I suppose when I retrieve it from the donor I might find my answer as well...

Edited May 24, 2021 by livemeyer
Was trying to add an image

[datzenmike]

I converted to a variable. Ran two extra wires for the adjustable.

 

It would seem to be cheaper to have all the option wiring on the harness than to have 500 possible option combinations at the factory. If an option isn't selected the plug just isn't used.

[livemeyer]

2 minutes ago, datzenmike said:

I converted to a variable. Ran two extra wires for the adjustable.

 

It would seem to be cheaper to have all the option wiring on the harness than to have 500 possible option combinations at the factory. If an option isn't selected the plug just isn't used.

Cool, it's good to know you did it, it can be done.  These two extra wires you mention, are they from the stalk/switch to the amplifier?  In addition to connecting that 2-wire plug at the multi-function switch? 

[datzenmike]

I switched the 720 wiring harness into the 620 so all the steering column switches would work. The harness was from a pre '83 truck but the dash was an '85. There were things that needed switching around. That earlier harness may not have had the two extra wires for the stalk switch so I made my own.

 

The variable delay wiper option was only available on the long bed??? Have you heard this? Charlie will know.

[Charlie69]

The variable speed wiper control is on the ST models but not all STs have this option.  I have 2 84 ST 2wd king cabs that have this option, my 2 86 ST king cabs 1 does one does not.  My 85 ST did not have it.  As for 83 and earlier not sure.  Of all 12 1980 720s I have owned none of them have had the variable speed wiper control.

 

[datzenmike]

Found it. There are 2 intermittent wiper amplifiers. One has to be the set delay but the other 28890- W7500 is for '82 and up King Cab GLs. There were standard, GL and Delux trim options. The GL has a J in the engine tag plate  as in KNL 720 JTU. 

 

Why only on the KCs????.... who knows.

[Charlie69]

Possibility is the king cabs had more options than the regular cabs.  There is also and intermittent wiper option that is not speed adjustable and my 86 has that type. My 84 & 85 both have the adjustable speed intermittent.