Wiring Question

[jdurham]

I have been having a little trouble with my 90. First, the dash is deteriorating, and cracking until I can no longer epoxy it back together On top of that, I lost my dash lights. I replaced the fuse and it blew it immediately. All other lights work fine. As a preliminary guess, I'd say it'll be the problem I've seen posted about the harness getting chaffed against the dash/steering column support. Here is the dilemma:



In my usual infinite wisdom I thought I'd go get the dash, dash wiring harness, and engine harness from my 93 donor to put in it. I removed everything from the donor, but I'm not sure how hard it'll be to get the sensors needed onto my 90 engine. I also read some recent posts about the computer engine management system being a problem as well as some other electrical issue with the later first gen wiring.



Keeping in mind that I intend to use the 518, a tach, and the cruise, should I repair my harness and wire the other things in myself, or should I use the 93 harness?



Also, If I use the 93 harness, how can I check the computer before using it?



Thanks!



Jim

 

["Mad Max"]

right vs left

JD - the right half of my brain which controlls the 'mad lunatic modify-everything/anything is possible' side says heck yeah it can be done. Then there's the left half which controls the 'any-wiring-newer-than-1973-is-no-fun' side which says 'well I haven't done it before so I have no idea how to help', so I guess I'd say, well, ummm, sure. I'd say though that yer on the right track with the whole wiring harness verses pieces of it. Heck dude, I just don't know.....

- S

 

[Greenleaf]

?????????????? ?????????????

 

[Philip]

Hi JD



First thing you need to look at is the hole where the wiring harness comes threw the firewall. If I remember right. The bulk head plugs are different configerations. So you would need to mod the firewall to get the the newer harness to fit and seal. Remember seal is the big point here. No seal means wet feet and rusted floor boards every time it rains



Moving the sensors shouldn't be hard. The mounts work between eather engine. All you would move is the TPS and RPM sensor.



The throttle linkage is different between the two years of trucks. To use the cruise off the 93 your going to have to change the throttle linkage to the newer version.



I have no idea of how to check that computer not on a truck. You could power it up off the truck. But with no sensors hooked up it. It would just throw a bunch of errors if you plug a scan tool into it.



JD I think I would have swaped the cabs if the 93 had a good one on it.

 

[jdurham]

I think I would have swaped the cabs if the 93 had a good one on it.

Good cab, but front fame horns pushed over. Can't decide which would be more work...



I'll look at the firewalls this weekend and we'll continue, but I still don't know which way would be better, although I lean toward the newer stuff...





Thanks!



Jim

 

[Philip]

Once you have the front sheet metal off. The cab only has four bolts holding it down. To remove and replace all the dash and wiring would take a lot more work. IMHO



But you also have to think of paint also. If both trucks are not the same color. If you don't do paint work. Then you would have to have someone repaint for you.





I do my own paint and body work. So switching the cabs for me is the easyer way out.

 

[jdurham]

Me too Philip, but mine is reg cab, and the body is extended. It sure would look funny with the bed hanging over the back like the old altered wheelbase cars! Believe me, if the frame was good, I'd be swapping, since the cab is so cramped on mine.



Jim

 

[tugboatphil]

Jim,



Having grown up in West Virginia, spent a career in the Navy, AND just being generally lazy, but prone to overcomplicate things..... (taking a breath), I'd take a good close look at the existing harness for obvious signs of worn insulation.



I once spent the better part of a day with my 90, on a road trip to D. C. For some reason the charge dropped well below 10V. I didn't pay iy much attention since I was driving in daylight. Well, I forgot about it when I stopped for fuel, just north of Richmond. I came back out and she wouldn't start.



My friend said that it probably needed a jump. Instead of listening, I flew into a frenzy, dropped the starter in the parking lot and took off hitchhiking. Got a ride down to Ashland, to a starter/ alternator shop. They bench tested it and it was good as new.



Hitched back up to the truck and put the starter back on. Walked over to the fuel pump and asked someone for a jump. Hooked them up and she fired right away.



Now the details of this are much more than mentioned, but I do this ALL the time. I just can't believe that something simple is wrong.



Since you already have the dash apart, try the simply fix first. You can always plan for the harness/ cab switch.



Just my $. 02.

 

[Philip]

Well that bites with the other cab being a extended cab. So it looks like your eather going to repair to old harness or try the swap out.



I would try the repair option first.