Steering Column Swap Help

[Super_Dave]

I am looking to possibly get an OEM 1986 tilt steering column for my 1974 C20 project. I need to get back to the seller with a decision and have done some rudimentary searches on the topic but don't have the luxury of time to keep hunting.

What I need to know is:

What issues do I need to be prepared for, such as wiring harness differences, etc.

I know that the 86 has a DD intermediate shaft, so I will need that from the donor.

What else do I need to do to make the swap? I am assuming the harness connection is different, is there an adapter or do you need to graft it in?

What about possible differences in the turn signal, possible wiper controls, etc?

I need to determine if I am borrowing more trouble that it's worth, so knowledgeable input with specifics is GREATLY APPRECIATED!

[73kay]

I have an 86 manual column in my 76. I modified my brights wires to fit on the column pretty easily even though I really liked the foot stomper. Wipers I'm still working on. I don't think you can get the exact compatibility with a late 80s wiper switch with the old 70s 2 speed motor. For now I ended up going back to the dash mount wiper switch. Other than that and the intermediate shaft you already identified it was pretty smooth. Just double check the wires match on the flat connector for the horn, turn signals etc.

[Super_Dave]

Just found out the intermediate shaft is not available, so I have to source one. Asked if his wipers were on the stalk and he said no, they are in the dash. Didn't know wipers were available on the dash in 86. Can anyone confirm that for me?

[73kay]

I thought 83 was the last year wipers were on the dash. Maybe the column isn't an 86? Hopefully someone will confirm some of what I've said to help ya out.

[11555wally]

I just recently changed my 86 from a regular column to a tilt. Bought what I was told was an 86 but I think it was later. Had the new column rebuilt by a great guy in Indiana who seems to be very knowledgeable about GM columns. The only problem I had was my truck had 2 speed wipers and the new column had variable speed wipers so he had to replace the switch inside the column which was costly. New column also had cruise which my truck didn't. but that was just pulling out a wire. PM me if you like and I can give you the guys contact info

[hatzie]

Use this as an opportunity to upgrade to a Jeep XJ U-Joint steering shaft. Google "XJ to Blazer steering conversion".

1983 was the last year of dash mounted wipers and floor button dimmer. 1984 has both on the stalk.
The Ignition and Neutral Safety switches are the same.

The turn, horn, brake, hazard, and Key buzzer connector is different after 1976 and probably changes several times... Didn't check between 77 & 87.

You can download the GM wiring diagrams for 1974 and the donor column from my manuals post.

It's not uncommon to update to 1979 or later cab harness to get rid of the glass fuses. You'll need the whole interior cab harness and at least the engine compartment plugs to mate the 74 harness with the 19?? bulkhead plug.
The wiper motor changed in 1978 to accommodate intermittent function.

[hatzie]

Originally Posted by 11555wally

I just recently changed my 86 from a regular column to a tilt. Bought what I was told was an 86 but I think it was later. Had the new column rebuilt by a great guy in Indiana who seems to be very knowledgeable about GM columns. The only problem I had was my truck had 2 speed wipers and the new column had variable speed wipers so he had to replace the switch inside the column which was costly. New column also had cruise which my truck didn't. but that was just pulling out a wire. PM me if you like and I can give you the guys contact info

He was partially correct. The truck harness will not plug directly into a delay switch column plug.
However... Changing the switch and stalk was unnecessary. You paid for a costly downgrade when it would've been fairly cheap to keep delay mode by purchasing a delay module and plugging it in.

On the 84 and up columns... intermittent or delay wipers are an easy upgrade. If the your new column is equipped with a delay switch buy a delay module and plug it in on both sides... Then go get a beer. The delay module literally plugs in between the delay column switch and the truck harness with no mods to the truck at all. The truck harness side connector is the same for delay and 2 speed wipers. The difference is on the column side. The wiper switch has two additional wires, a delay potentiometer in the switch, the delay stalk and, the connector that mates with the switch side of the delay module rather than direct to the truck harness.

[11555wally]

Thanks for the info Hatzie. I think I paid $40 for the new switch. Column turned out nice.

[hatzie]

The 15598496 delay module costs around $75 so changing the $40 switch etc was cheaper. I assumed "costly" meant $100 or more.

[Super_Dave]

As much as I want to take a run at the column, the seller says he bought the truck in 1986 with 16K on the odometer and a dash mounted wiper switch. When pressed about the year discrepancy, (LMC and others list 1984 as the first stalk mounted wiper arm), his answers have been 'minimal' to the point it raises concerns or no reply. I usually steer clear when that happens.

Anyway, thanks for the info. I will squirrel it away for future use.

[hatzie]

If you aren't afraid of re-pinning the harmonica plug it gets easier to find a column that'll fit because you aren't limited to 73-76. You can use 77-83 columns with some head scratching and you don't have to move the dimmer and wiper controls unless you want to.

[Super_Dave]

Originally Posted by hatzie

Use this as an opportunity to upgrade to a Jeep XJ U-Joint steering shaft. Google "XJ to Blazer steering conversion".

I remember this now... thanks for the reminder. I have my son keeping an eye out for one at the yard where he works.

Anyone familiar with Chevy Van tilt steering column swaps into a square?

[Super_Dave]

Originally Posted by hatzie

If you aren't afraid of re-pinning the harmonica plug it gets easier to find a column that'll fit because you aren't limited to 73-76. You can use 77-83 columns with some head scratching and you don't have to move the dimmer and wiper controls unless you want to.

American Wire claims to have an adapter kit for the harness plugs... sent them an e-mail specific to my needs... waiting to hear back.

As for re-pinning, I can do almost anything with enough drawings, videos and pictures!

[hatzie]

G series van columns could be a real challenge. They're mounted at a much different angle so the the firewall flange is not even close.
The G series ignition was in the dash too... at least on the 70's G vans. Never worked on the 80's or 90's models so...
I believe the column is shorter as well but don't quote me on that. IRTRTBW.

[Super_Dave]

Okay, the dude gets back to me and says the truck is an '83 he bought in '86 with 16K miles. Tells me it was a 4x4.
So, if that is indeed true, the wipers are two speed in the dash, correct?
It also means I can just plug-n-play the harness connector, correct?
Any difference between 2WD C10/20 and a K series?
I will still be able to use my intermediate shaft until I do the Jeep conversion.

For a C note, I think it might be worth grabbing to get a factory tilt automatic column.

[hatzie]

You'll have to re-pin the harmonica plug on the truck or on the column... Your choice.
1983 could've had delay wipers on the dash but it makes zero difference to the column.

Automatic or Manual transmission makes a difference but C or K series doesn't.