This week I started tearing into my 740, and found some things I would have rather not found…anyways looks like the the previous owner hacked up the stock wiring harness pretty good, so I'd like to get it back to stock format.
At least it was hacked up in a way that I know which "mods" were his…wait till you see these joints. Hilarious.

Here are my questions:

1. Can anybody provide me photos of what the pass side power harness should look like?

2. Where can I find me some wiring diagrams for this old girl?

3. Was there ever a stock electric fan mounted in FRONT of the rad on these cars? (I'm guessing not, and that it's also the prev owner's handy work)

4. Not really a question, just wanted to show you the awesome joints:





Last but not least…gave the interior some TLC

 

electric fans started in 1992, along with a bigger radiator and some other stuff.

1990 is a transition year

the best wiring diagrams are the Volvo 'greenbooks', they are specific to the model year. Unluckily, Volvo greenbook TP31571/1, the 1990 740 Wiring Diagrams, is out of print and no longer available from Volvo.

There is a DVD of all 740 documentation from VCOA, but I don't know if it has the 1990 wiring diagrams on it or not. I have the DVD of 940/960 docs, as well as 240/260, the 9x0 book has all wiring diagrams, while the 240 is missing a few years in the early 80s.

 

Thanks for the info Pierce. Volvotips.com seems to have what I'm looking for…tons of schematics over there.

If anyone happens to have pics of what the harness should look like (where **** belongs!!!) I could really use them. Will send Canadian beer...

 

well, you can see some of the harnesses here on a 1991 turbo... things are moved around under the hood on a turbo, the battery and airbox are swapped.



basically the harnesses look like black tubes as all the wires are inside.

i'm kinda surprised to see that much hacking on a 1990, the bad wiring years were 81 through 1987, and in 1988 they improved the insulation, and later cars usually are fine.

 

Looks like someone gave it the ol' chop and then they had to get it back together. You good with a soldering gun and heat shrink?

In front there is one on my 89 740 wagon, so I think that's pretty stock.

The actual engine wiring harness should be pretty much the same. You got LH2.4 fuel injection and EZK116 ignition by the looks of things, so the engine wiring harness should be the same for an 89 740 naturally aspirated car with the same setup.

This is a master diagram for my car: https://skydrive.live.com/redir?resi...t=photo%2c.gif

So it includes all variants of the car for all markets in the 1989 model year. Different fuel injection, ignition, turbo, nonturbo, north American lighting and euro, etc. You can find your systems on it and follow the color codes.

This one is a little different: https://skydrive.live.com/redir?resi...t=photo%2c.gif

It is just the LH2.4 and EZK116 systems for a naturally aspirated car with a few modifications. I used this diagram to run a 1994 940 turbo engine on an engine stand. The only differences were the injector ballasts (only on turbo cars, so they are not on the diagram) and that the coil gets power from the radio suppression relay (or injector relay). As a note, dotted lines are for optional stuff, like egr (only in California).

For using a non turbo diagram on an engine 5 years after mine it seemed to all match. One or two colors may have been different, but if you can trace both ends you can make it work.

 

Thanks for the pics and diagrams guys, Titan Joe that's one hell of a master schematic! Also, Titan Joe, soldering and heat-shrinking it up is one of my favorites ;-)
As soon as I get these circuits straightened away, I'll be off to the races.

As for the extra fan that was in front, I already ripped it out, the wiring could not have been stock, and it was rigged up with zip-ties (not cool)…Is the clutch fan not enough to cool these engines down?

I found one of these fancy greenbooks on ebay for a 1990 740…100 bucks though. I guess that would be a good investment though?

One more side-note…When did they change the headlights in these cars? I prefer the set like the ones in your avatar pic (Titan Joe)

 

I use *black* zipties all the time on automotive stuff, they are just fine. don't use the clear white ones, they rot.

your 1990 would be very hard to change the headlights on. they changed the fenders, hood, and grill in 1990, and again in 1991+, so 1990 is a one-of year.

 

Well that's that! Keeping the ones I have in there! lol
I'm getting ahead of myself but do any of you guys run HIDs in the stock housings?

 

re HID's in halogen reflectors. absolutely NOT. wrong light pattern, will blind oncoming traffic and put too much light in the middle and not enough on the sides, with way too messed up of a cutoff pattern.

HID's need to be projector lamps, or properly engineered HID specific reflectors. here, this guy says it better than I can, Daniel Stern Lighting Consultancy and Supply

now, someone on here took some volvo rectangulars, and hacked them and installed HID projectors inside them. looked very trick.

 

That makes my day.

The aux fan really doesn't do much. I have to idle for 10 minutes or more on a really hot day for it to kick on. Mine didn't work for more that10 years before I fixed it in high school, so I doubt you'll miss it.

I'm really lucky to have a full set for my car my dad bought new with the car. Some you can find online. Buying for 100 bucks I think is steep. I try to scan more and more of mine in as people need them. There are a lot of pdf's online for 240s. You may find some nuggets here: Volvo Wiring Diagrams


That was meeeeeeeeeeeeeeeeeeeeeeeeeeeee! (said like a little kid riding a sled down a hill)

It would be hard to figure the same setup for the later 90+ front end like pierce said. But the sky really is the limit if you can fabricate. Here's a link to my thread on my lights: https://volvoforums.com/forum/volvo-...9-740-a-70454/

 

the aux fan on cars that still have the mechanical fan, are there mostly to help the air conditioning. drive the car on a hot day in stop and go traffic with the AC on high and disable that fan and watch the engine temps go through the moon.

the 92+ cars, like my 1992 turbo 740 wagon, don't even HAVE a mechanical fan, instead they have a 2 speed electric fan.