My '86 740's ignition coil made contact with the strut tower and grounded out really nicely. The positive wire going back through the firewall got toasted all the way back to the fuse panel, how would I go about removing this wiring harness?

 

there's a big rectangular plug where it goes through the firewall, no? dunno I don't have wiring diagrams for early 740s....

 

Thanks for responding so fast! MVS wasn't being too friendly when I asked for help. From my inspection, no. That's for the engine wiring harness, the ignition coil wiring goes all the way through some rectangular plug behind the glovebox (it burnt part of that up too) and then to the fuse panel. So I need to remove basically the entire right side of the cars wiring.

 

probably start at the ICU, wherever that is on that year/model. I thought on early 740's the ICU (ignition control unit) is behind the glovebox near the ECU, on later ones its over on the other side. I only have wiring diagrams and parts locaters for 1991+ 740's which are really 940's. the coil signal wire (pin 1) comes from power module, which in turn is driven by the ICU directly, while the coil power wire (pin 15) should come directly off the ignition switch somehow, I don't think its relay driven or fused.


on a 92 740T (mine), its battery to the positive terminal (on the firewall in back of the instrument panel) to the ignition switch to connector A to coil pin 15. Connector A is a big 50-something pin block connector near the righthand A post. has everything on it from headlights to ICU/ECU signals. Wait, on a 92 turbo, its connector B which is lefthand A post, and the coil is also connected through a 8 pin connector 'F' thats at the suspension tower.

yea, lotsa variations, and both those 92 cars are LH2.4, while you probably have LH 2.2.

 

I do indeed have LH2.2, stupid question, but is the ICU the little metal bosch thing with the black top on it near the air box? I think that's the ICU.

 

Nevermind, it is that thing, should've google'd it first, haha. Anyway, I'm fairly sure I looked at that and didn't see any of the wires leading to it were cooked, what looks to be tha major issue here is a blue wire with a red stripe going through it. it goes from the bottom right fuse in the fuse panel over to a very large multipin connector behind the glovebox, and then to the ECU and through the firewall.

 

this is a 740? pretty sure the ICU is under the dashboard. LH2.2 240's have a chrysler ICU over behind the right headlight. but pin 15 which is the wire I think you're describing, comes from the ignition switch, not the ICU. it might connect to the fuse panel, but I don't believe its on a fuse. the module you found sounds like the power module, which is like an ignition amplifier, its driving coil pin 1, usually with a red/white wire.

 

ok, found this.
http://www.k-jet.org/files/greenbook...incomplete.pdf

onj page 170 and 171 of 211 is the 'generic' wiring diagram and component locator for the EZ-117K ignition system used with LH 2.2 injection on US models (there's also a Rex system that was used, but its completely different).

the ICU is component 260. I think what you found was component 419, the ignition power module aka amplifier. I think the wire you fried is the BL (Blue) wire off coil pin 15 that goes through a connector and connects to the blue-red wire off ignition key pin 15R.

 

Ahhh, I didn't know there was even another box. I just assumed it was just the ecu down there because I've never seen anything else. The coil wire drawing too much amperage wouldn't have damaged the ICU, would it have? I don't know of many other 740's of my vintage in the junkyard. Also a pinout for the ignition switch wiring would be wonderful. I took that apart too because of the melted wire going to it. Thank god the wire didn't get hot enough to penetrate the main positive wires insulation, it would've started welding things then.

 

ah. here's a 1987 740 wiring diagram, should be pretty close to your car.
http://www.volvowiringdiagrams.com/v...20Diagrams.pdf

page 6 shows the ignition switch wiring.

note that in euro cars, circuit 30 means battery +, circuit 15 means switched power (on with ignition). 50 is start. 15R is on in run or start, while X is on in accessory or run.

your non-turbo fuel injection should be on page 20-21, ignition on page 34-35