8 cylinder front engine iconic vehicle
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By jschiller
#116010
I need a readable version of the 89 current flow diagram. The one I have is very indistinct in places and the circuit I need help with is very bad.
I am troubleshooting a no power issue to the interior lights which involves fuses 7 and 24 and maybe relay IV (can't read the number on the diagram). I think I can only use the 89 diagram because the 88 and 90 cars have a different layout. I am especially interested which lower connector is supposed to feed the lights on the 30 bus as i think that is my problem. Thanks if you can help.
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By worf
#116098
Even the official WSM paper wiring diagrams are indistinct. The PDF version are only useful in emergencies.

You are correct that you need ‘89 diagrams and that ‘88 or ‘90 won’t do; the ‘89 has some unique-to-it wiring.

List any specific questions you have in addition to those above and I’ll see what I can do. Stay tuned.
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By worf
#116149
jschiller wrote: Sun Nov 14, 2021 11:53 am I am troubleshooting a no power issue to the interior lights which involves fuses 7 and 24 and maybe relay IV (can't read the number on the diagram). I think I can only use the 89 diagram because the 88 and 90 cars have a different layout. I am especially interested which lower connector is supposed to feed the lights on the 30 bus as i think that is my problem. Thanks if you can help.
Interior lights get 30 bus from fuse 24. No other power sources.

Fuse 24 feeds E12, and E11. E11 doubles back to E23. E23 feeds T11 and relay XXI (Inside Light Relay) 30a pin. (Fuse 24 may also feed other components, but I didn't check sheets other than "Lights USA.")

Grounds for interior lights are: MP VI (spare tire well) V (CEL), IV (steering column) ... and likely one or two more.

E12 feeds door panel lights, door end lights, lock/alarm LED.

T11 feeds roof and hatch.

XXI provides switched ground to all the 3-position lights.

HTH.

All that -^ according to WSM '89 wiring diagrams. I have found errors in the '89 diagrams. I suggest checking continuity for circuits to confirm correctness of my above summary of the diagrams before making decisions on other findings.
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By jschiller
#116179
^^Thanks Dave. I very much appreciate the info. That helps immensely.
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By jschiller
#116643
Thanks, Fred. Unfortunately, there are substantial differences between the 89 and 90 MY. And, since the MY 89 diagram is known to be wrong in places, you never know if the differences are errors until you trace each current path. I think starting with a readable MY 89 is the best thing I can do, if I can find one. Maybe someone with a full set of the WSM in paper will post one someday if it exists though Dave hints that it might not.
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By hessank
#116655
Mine is an 89 also and in the absence of an 89 diagram I have found these to work for me over the past 10 years.
There is very little difference between the 89 and 90 except for some of the digi-dash and 4 stalk turn signal/wiper controls(89 is a unicorn in this respect)
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By worf
#116735
jschiller wrote: Wed Nov 17, 2021 11:34 am Maybe someone with a full set of the WSM in paper will post one someday if it exists though Dave hints that it might not.
I could scan the paper ‘89 WSM diagrams. The problem is that the actual diagrams for the ‘89 are the worst of the bunch and unless it’s done at at least 600 (if not 900) DPI it’s going to look like poop. My scanner’s are 300 DPI.

A million years ago, I paid $100 (IIRC) Kinkos to copy-with-expansion the paper diagrams onto 22”x34” format. Didn’t help much. If I can find that roll of paper I can send them to you for shipping cost.
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By worf
#116737
hessank wrote: Wed Nov 17, 2021 12:17 pm There is very little difference between the 89 and 90 except for some of the digi-dash and 4 stalk turn signal/wiper controls(89 is a unicorn in this respect)
The ‘89 is more half-‘88 and half-‘90 than mostly’90. And the “interface” is unique to ‘89. Look through pet, almost all - if not all - wiring harnesses are ‘87-‘88, ‘89, ‘90-‘’95.
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By jschiller
#116760
worf wrote: Wed Nov 17, 2021 3:29 pm
jschiller wrote: Wed Nov 17, 2021 11:34 am Maybe someone with a full set of the WSM in paper will post one someday if it exists though Dave hints that it might not.
A million years ago, I paid $100 (IIRC) Kinkos to copy-with-expansion the paper diagrams onto 22”x34” format. Didn’t help much. If I can find that roll of paper I can send them to you for shipping cost.
Dave, I would be grateful to get it if you locate it. Don't stress over it, though. I've got plenty to keep me busy besides the interior light problem. I'm slowly reassembling the interior after a full rehab; seats, carpet, dash, console, HVAC and I'm testing as I go. Newest find is a bad recirculating box vacuum actuator that I already replaced once, so the box is coming out...again :surrender: So the CE panel has to come out again and maybe I'll get lucky on the lighting problem.

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