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Username Post: 1985 C10 HD 4spd reverse light switch        (Topic#357963)
Mad Professor 
Contributor
Posts: 101

Reg: 12-30-08
09-07-19 06:48 PM - Post#2775019    

I'm still working out the bugs to get RMV inspection. Truck has HD 4spd with top mounted shifter (M465?)

I think/hope getting the reverse lights to work will be last problem.

Both lamps are new. Outlets have good grounds. I stripped a patch of the + wire to test 1 outlet. I get a good ground from + wire, through outlet/lamp so lamp and outlet are O.K.

Reverse lamp switch is pretty well hidden where it mounts on transmission. Here is current plan:

1) Clean off grime so I can see/unplug switch. Tight quarters here.

2) Jump the wires on plug to see if lights work (tests wires from fuse to lamp outlets). If lights work eliminates wires from fuse to light outlets. Turn signals are on same fuse and they work O.K. Clean switch/plug terminals, check lights again

3) Replace reverse light switch. This looks to be very tight space. Will I be able to get at it with a deep socket? I don't see any way with a combination wrench. It's hard just to get a hand up there to feel the switch/plug

4) Not sure if there is an access plate above shifter hook up? Nearly new interior new shifter boot with full rug. Prefer not to hack this up or cut holes in floor.

Anybody have picture of the switch mounted on transmission? Might help with working with "blind" fingers in a place I cannot see.

Thoughts and suggestions are appreciated.



62 Willys wagon
67 CJ5 Buick V6 w/OD
68 Camaro RS/SS , 69 LT1 350, M22
73 C10 292 6, M21 muncie/hurst, 3:73 posi
89 S10 baja package







 
gchemist 
Senior Chevytalk Moderator
Posts: 24894
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
09-09-19 06:35 AM - Post#2775128    
    In response to Mad Professor

I have no idea on how reverse works on a manual transmission. I'll have to learn from your post. I'll dig out my '83 service manual and thumb through it.

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles


 
Mad Professor 
Contributor
Posts: 101

Reg: 12-30-08
09-09-19 08:28 AM - Post#2775134    
    In response to gchemist

Thanks for the reply.

I have a 1984 C/K truck service manual. I is not much help. It is missing the last pages with the wiring diagrams, but I already have those.

I've had cars (camaro nova)/trucks (C ) with M/20 21 22 muncie 4spds.

The reverse light switch mounts on the transmission housing and contacts the lever/linkage that shifts into reverse. Never throw one out as they are hard to find and new are $$$. But at least they are easy to get at.

My 85 has the HD 4 spd SM 465. The shifter goes into the top of the transmission with no linkage.

The reverse light switch screws into the side of the transmission. You can't see it from underneath the truck, just the 2 wires and plug that connect to it. It's really tight just to get your arm up in there to touch the plug.



Switch is on driver side near top, just in front of shifter. I don't think I can get at it from the top, and don't want to cut away metal on the floor.

One wire runs to fusebox that is common fuse with directionals, which work. The other wire runs back to the sockets/light bulbs.

Every once in a while the lights work. I don't think it is an open in the wires. Before I try to pull switch I'm going to jump the plug and see if the lights come on to be sure.

I'm waiting on the switch first, as I don't have a lift, and will be blocking up the front wheels to get some room to work with underneath.

Worst case, I will have to drop driveshaft and crossmember, so I can lower the transmission.

Anyway , still hoping someone out there has done this in the past.

Thanks.




62 Willys wagon
67 CJ5 Buick V6 w/OD
68 Camaro RS/SS , 69 LT1 350, M22
73 C10 292 6, M21 muncie/hurst, 3:73 posi
89 S10 baja package







 
Keith Seymore 
Contributor
Posts: 728
Keith Seymore
Loc: Southeast Michigan
Reg: 09-17-08
09-10-19 08:36 AM - Post#2775240    
    In response to Mad Professor

  • Mad Professor Said:


Worst case, I will have to drop driveshaft and crossmember, so I can lower the transmission.






Peel back the carpet and see if your truck has the removeable floor hump.

If it does that would allow you to do all this from the top side rather than underneath.

You might even be able to see the attachments for the floor hump from the underside, if they are present.

K




Chevelle Intro: http://www.popularhotrodding.com/features/1005phr_...
My Pontiacs: http://forums.maxperformanceinc.com/forums/showthr...
Pickup: http://67-72chevytrucks.com/vboard/showthread.php?...


Edited by Keith Seymore on 09-12-19 07:45 AM. Reason for edit: No reason given.

 
Mad Professor 
Contributor
Posts: 101

Reg: 12-30-08
09-10-19 01:39 PM - Post#2775268    
    In response to Keith Seymore

Thanks Keith,

I don't think it has access plate, it's 1/2 ton.



Truck is too pristine to hack up. I'd post pics but can't here from my computer. I don't do crapbucket and such.

If there is another way to download images, let me know

62 Willys wagon
67 CJ5 Buick V6 w/OD
68 Camaro RS/SS , 69 LT1 350, M22
73 C10 292 6, M21 muncie/hurst, 3:73 posi
89 S10 baja package







 
Keith Seymore 
Contributor
Posts: 728
Keith Seymore
Loc: Southeast Michigan
Reg: 09-17-08
09-12-19 07:30 AM - Post#2775383    
    In response to Mad Professor

  • Mad Professor Said:
Thanks Keith,

I don't think it has access plate, it's 1/2 ton.




It's not driven by 1/2 ton or 3/4 ton.

It's a function of high hump vs low hump.

All column shifted 2wd (ie, automatic or three on the tree manual) got low hump (which is all stamped as part of the floor pan).

All floor shifted manual trans (ie, MY6 overdrive or M20 granny gear) and/or 4wd got high hump.

The trick is to figure out if your high hump is removeable.

K

Chevelle Intro: http://www.popularhotrodding.com/features/1005phr_...
My Pontiacs: http://forums.maxperformanceinc.com/forums/showthr...
Pickup: http://67-72chevytrucks.com/vboard/showthread.php?...


Edited by Keith Seymore on 09-12-19 07:43 AM. Reason for edit: No reason given.

 
Keith Seymore 
Contributor
Posts: 728
Keith Seymore
Loc: Southeast Michigan
Reg: 09-17-08
09-12-19 07:43 AM - Post#2775385    
    In response to Mad Professor

  • Mad Professor Said:


If there is another way to download images, let me know



I certainly don't know.

I added pics to another thread thirty seconds before attempting it here; it worked there but not in this one.

K


Chevelle Intro: http://www.popularhotrodding.com/features/1005phr_...
My Pontiacs: http://forums.maxperformanceinc.com/forums/showthr...
Pickup: http://67-72chevytrucks.com/vboard/showthread.php?...


 
49erman 
Poster
Posts: 71

Loc: So Cal Lower Desert
Reg: 01-02-18
09-12-19 12:08 PM - Post#2775397    
    In response to Keith Seymore

  • Keith Seymore Said:
  • Mad Professor Said:


If there is another way to download images, let me know



I certainly don't know.

I added pics to another thread thirty seconds before attempting it here; it worked there but not in this one.

K




In this Forum to post pictures you HAVE to BE a PAYING MEMBER, your other forum that allowed you and most other forums aren't setup for greed like this one is. Others are just Happy to get new members..



 
Keith_Knox 
Moderator and "17th Year" Gold Supporting Member
Posts: 6194
Keith_Knox
Age: 78
Loc: Napa, Ca USA
Reg: 04-02-00
09-12-19 07:17 PM - Post#2775424    
    In response to 49erman

Not true. You can use a hosting site. Here are Tony's instructions to post pictures.

https://www.chevytalk.org/fusionbb/showtopic.php?t...

29-41, 42-48, 49-54 Moderator
1948 Chevy Fleetmaster Coupe Purchased 6/2010. Stock with rebuilt 52 216 installed May 1966.
1946 Chevy 1/2 ton pickup, stock. Purchased 11/18/17.
2019 Ford Ranger Lariat Super Crew


 
Keith Seymore 
Contributor
Posts: 728
Keith Seymore
Loc: Southeast Michigan
Reg: 09-17-08
09-13-19 10:24 AM - Post#2775458    
    In response to Keith_Knox

  • Keith_Knox Said:
Not true. You can use a hosting site. Here are Tony's instructions to post pictures.

https://www.chevytalk.org/fusionbb/showtopic.php?t...



Upon further review - it appears to be a problem with Photobucket and the new photo, not Chevytalk.com.

No big surprise there.

K


Chevelle Intro: http://www.popularhotrodding.com/features/1005phr_...
My Pontiacs: http://forums.maxperformanceinc.com/forums/showthr...
Pickup: http://67-72chevytrucks.com/vboard/showthread.php?...


Edited by Keith Seymore on 09-13-19 10:34 AM. Reason for edit: No reason given.

 
Mad Professor 
Contributor
Posts: 101

Reg: 12-30-08
09-14-19 08:08 AM - Post#2775499    
    In response to Keith Seymore

Update.

I have the switch but doing this outside so working around rainy days.

Thursday (rainy)had a problem with woodchuck in garden and bees ( I'm allergic). I chased woodchuck under a porch, then got into a bee nest. Reaction was bad enough I almost used my epi-pen. A sting on my finger swelled about 1/2 way to elbow. 2 other stings, not as bad.

I usually take a benadryl and don't get a bad reaction, was out of benadryl.

Waiting for swelling to go down, work on truck Sunday.

I'm hoping truck has the removable pan. I have the build sheet and it is factory HD 4 spd.

62 Willys wagon
67 CJ5 Buick V6 w/OD
68 Camaro RS/SS , 69 LT1 350, M22
73 C10 292 6, M21 muncie/hurst, 3:73 posi
89 S10 baja package







 
Keith Seymore 
Contributor
Posts: 728
Keith Seymore
Loc: Southeast Michigan
Reg: 09-17-08
09-17-19 07:47 AM - Post#2775702    
    In response to Mad Professor

  • Mad Professor Said:


I'm hoping truck has the removable pan. I have the build sheet and it is factory HD 4 spd.



Sorry about your incident. I'm allergic to wood chucks, too.

At your leisure - could you post a pic of the build sheet, for posterity?

Thanks,

K


Chevelle Intro: http://www.popularhotrodding.com/features/1005phr_...
My Pontiacs: http://forums.maxperformanceinc.com/forums/showthr...
Pickup: http://67-72chevytrucks.com/vboard/showthread.php?...


 
Mad Professor 
Contributor
Posts: 101

Reg: 12-30-08
09-17-19 02:43 PM - Post#2775738    
    In response to Keith Seymore

Woodchucks are all getting lead poisoning. Wasps have been sprayed 3 times and almost all gone, they are up in the wall.

My hand/arm just got swelling down today. So I blocked up the front wheels and think? I might be able to get the switch out from underneath.

New switch was from NAPA, box had correct part # so I didn't bother checking it. Opened up box and wrong switch, not even close, new one ordered and in tomorrow afternoon. Floor pan does not have any sort of access besides shifter boot.

I'll need to scan the build sheet and find a site/place to host the files. Also have pics of the truck. I got disgusted with photobucket years ago.

62 Willys wagon
67 CJ5 Buick V6 w/OD
68 Camaro RS/SS , 69 LT1 350, M22
73 C10 292 6, M21 muncie/hurst, 3:73 posi
89 S10 baja package







Edited by Mad Professor on 09-17-19 03:08 PM. Reason for edit: No reason given.

 
Keith Seymore 
Contributor
Posts: 728
Keith Seymore
Loc: Southeast Michigan
Reg: 09-17-08
09-19-19 04:36 AM - Post#2775868    
    In response to Mad Professor

  • Mad Professor Said:
Woodchucks are all getting lead poisoning.



LOL - I tried that too but ended up shooting my barn full of holes. In my defense - it wasn't my rifle that I was using (but: I WAS able to hit the broad side of a barn. It just happened to be MY barn).

  • Mad Professor Said:


I'll need to scan the build sheet and find a site/place to host the files. Also have pics of the truck. I got disgusted with photobucket years ago.



Let me/us know what you come up with. I am also being held hostage by Photobucket (two separate accounts) and am interested in something different.

K



Chevelle Intro: http://www.popularhotrodding.com/features/1005phr_...
My Pontiacs: http://forums.maxperformanceinc.com/forums/showthr...
Pickup: http://67-72chevytrucks.com/vboard/showthread.php?...


 
Mad Professor 
Contributor
Posts: 101

Reg: 12-30-08
09-19-19 06:24 PM - Post#2775920    
    In response to Keith Seymore

Well still working on it and still a bit frustrating.

Here is a link to wiring:

73-87 wiring

I got front end up and crawled under.

Can barely see plug for reverse switch. One arm only access. I made some scrapers, used a tooth brush and rooted around where the switch was and blew out with air a few times. Then sprayed out with contact cleaner.

A little hard to get connector off, but could get a 7/8" deep socket on switch, and switch out.

Switch tested out good. Open or low ohms when off/on, respectively. Also got bat voltage when hooked up to bat and on.

Tried jumping connector with key on, no lights. PITA just to get a jumper up there a weather pack connector.

Tried to work through wiring diagrams. LtGRN is hot to lights, dkBlU hot from fuse. Same fuse as directional, which work. Fuse is not hot unless ign key is on.

I found a set of LtGRN/dkBLU wires coming from bottom of steering column, to a 2-wire plug connector near brake pedal. Wires from there went through cowl just under clutch linkage.

On cowl side, another 2-wire connector that went up through the same holder as the w/wiper hose, then back under cowl to wires to rear of truck. Still same colors. Connector was in bad shape and I took apart and cleaned it up.

With key on dkBlu wire from cowl has bat voltage.

I thought bad connector was problem so I spent an hour or so cursing underneath truck to get switch back in. Switch has a thin gasket where it mounts to tranny. After dropping switch/swearing/looking for gasket a few times, I took some RTV sealant and secured gasket to switch. Finally got switch threads started and installed. This is working blind by feel with one hand. PITA to get plug hooked up too.

Turned on ign key, put in reverse still no lights.

At this point getting dark and mosquitoes getting bad.

I either have an open someplace, or the PITA plug on the reverse switch might not be making good contact.

The wiring diagrams are a little confusing. I'm assuming with ign key on, dkBLU wire from column feeds down to switch on tranny, which when on/in reverse, feeds power into ltGRN wire. Back up to the column in ltGRN wire. Then feeds lights like an auto or 3sp in the tree.

I think GM may have did it this way so harness is more in common with auto/3spd. I'd have run ltGRN wire from reverse switch right back to the lights underneath.

Anyway.........more fun and games tomorrow with the multimeter.

62 Willys wagon
67 CJ5 Buick V6 w/OD
68 Camaro RS/SS , 69 LT1 350, M22
73 C10 292 6, M21 muncie/hurst, 3:73 posi
89 S10 baja package







 
Mad Professor 
Contributor
Posts: 101

Reg: 12-30-08
09-20-19 05:08 PM - Post#2776006    
    In response to Mad Professor

Wiring is as I thought it was.

Fuse common with directionals, dkBLU wire feeds power into steering column(can't see this, only live ingn key on), it/dkBLU comes out paired with a ltGRN wire w/2-wire connector.

These wires go through firewall under clutch mech, to another connector to wires that go to reverse switch on tranny. Connector near wiper fluid lines. This goes to connector on tranny switch.

The ltGRN wire on tranny switch feeds power back up to ltGRN on steering column connector. Then into wiring harness back to lights ltGRN wire.

My open was a bad connector at tranny switch. Not enough room to get one arm up there to even test stuff.

I'm pulling whole two wires (BLU/ltGRN) from firewall to tranny switch, to solder in a new connectorto tranny. No way to do this underneath. I solder, liquid electrical tape, then shrink tape over that. Connector will be in tomorrow.

Anyway, you can pull the switch from underneath, but is a PITA.

I hope what I posted makes sense if anyone has to troubleshoot wiring.

62 Willys wagon
67 CJ5 Buick V6 w/OD
68 Camaro RS/SS , 69 LT1 350, M22
73 C10 292 6, M21 muncie/hurst, 3:73 posi
89 S10 baja package







 
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