pipedown

No its not stuck on, its stuck off. It does not illuminate briefly when you
start the truck and thus will not pass a smog check in CA.

I'll be fixing this 1988 Ford Ranger P/U this weekend and having done some
homework already, I still need a tip. As background this truck did have a
problem where it just stalled out and wouldn't start again. That problem
was traced to a wire harness that came loose and got burned on the manefold
causing (at least) one of the wires to go open. Evidently the one needed to
keep things running. That was fixed through visual inspection with a little
help from a Ford explorer 1993 shop manual.

Now I suspect the check engine light problem is the same cause (open wire in
harness) only I don't know which wire to trace. I checked several repair
guides and none show the check engine light and what wire it is associated
with it. If I could just determine the color and connectors it runs through
this would be easy.

I'm not usually one to suspect conspiricy but really. WRT the ECC and
associated sensors and idiot lights; Chiltons and Haynes only show a picture
of some parts and say its too complicated to troubleshoot. OK expected.
The FORD shop manuals for my 93 Explorer have a single page saying check the
third manual (you don't have). The EVTM (electrical/vacuum troubleshooting
manual) for the 84 Ranger (by ford again) shows most of the wires to the ECC
but not the idiot light (check engine).

If anyone has the ECC repair manual for just about any ford truck (ranger,
bronco II, Explorer in the 1983 to 1993 range you can probably determine the
wire color for me.

Yes, I will check the bulb first. So far I have only visually traced the
wire harness back to the ECC so it seems likely there is another open wire
in there.

My second option is to trace the wire from the lamp back to the open using a
signal tracer (triplett fox and hound). That will work but at the cost of
more effort.


Does anyone have any insight as to why this indicator lamp would be excluded
from most service manuals.

scrape

Nope other than Haynes and Chiltons are not the first place I'd go
for schematics.

Check out http://www.eautorepair.net. It's the online version of
Mitchell On Demand and has the *actual* schematics. You can buy
one week, one month or one year subscriptions. One week is $10, I
believe. I just got a one month subscription for one of my
vehicles for $15.00. and you can print whatever you need to,
although I'm not sure how you'd go about downloading anything.

whitelightning

Does it come on if you force a code, like say unplug the engine
coolant sensor
once tghe engine is at operating temp.

Whitelightning

jeff strickland

Have you considered the possibility that the bulb is burnt out?

My vehicles turn the bulb on with the Ignition ON. The light goes out on my
Jeep and my Mazda (a '94 and a '93, respectively) turn the light on with
Ignition ON, then the light goes out after a few seconds. My '94 BMW turns
the light on and keeps it on until Ignition START.

If your Check Light never comes on, the first check is the bulb. You had
trouble previously though, so you may want to look at the melted wires again
to be sure they were all fixed.

david

On Tue, 13 May 2008 13:00:20 -0700, pipedown rearranged some electrons to
say:

http://www.autozone.com
Select "repair info"
You can get a basic wiring diagram there.

According to that, 1988 Ford Ranger, 4 cyl, check engine light is a pink
wire going to pin 20 of the engine control module. The high side of the
bulb is protected by a 10 amp fuse (fuse #10), check that fuse to make
sure it is OK.

pipedown

No Chiltons and Haynes were my last try and just about all they had at the
library ( I sent the friend whose truck I am fixing). I may try a
subscription service if things get hairy next week but the friend is poor
and we don't want to spend much if anything. Registration is payed. just
need to pass smog to get a sticker, they give you a bit of time to clear
that up.

pipedown

I may try that but I suspect it will not. Seems like an easy test though.

Its either the bulb (maybe a fuse), wire or controller and I will check them
in that order.

pipedown

Duh, re read, I plan to check that first

pipedown

That's a pretty good website but a little slow for me. I am still looking
for the source diagram (do you have an exact link?) you quoted the pink wire
but that info should be useful in and of itself. Thanks

jeff strickland

I would not expect the Check light to be on its own fuse. It should get
ground to turn on from the computer -- the pink wire -- If this is true, the
pink wire should show 12v if the light works.