another possibility

Topic: another possibility (Read 1274 times) previous topic - next topic

another possibility

June 06, 2006, 07:46:58 PM

ok i was checking my wires and started testing them with a test light. I ran the codes earlier which Im still not sure on but it mentioned something about main circuit failure. I got to checking my wires after that. the black and orange wire going into my EEC power relay has power which it should it looks like a constant hot to me, the Red and light green coming from the ignition switch is hot as well with the key on. the black and light green does nothing as its a ground. the nifty part is the black and yellow which runs to what I would think is the main power wires has nothing with or without the key on. So does that mean the relay is shot? If so would one of the 3.8 harness I had work? thanks

another possibility

Reply #1 – June 10, 2006, 11:51:42 AM

it sounds like you have the circuit correct from looking over the wire colors in my evtm.

I would recheck the coil ground on the relay,, BK/LG. The EVTM calls out the final termination of the BK/LG is located at the RH Fender apr0n near battery.

I would undo the BK/LG wire there and check continuity from the EEC power relay connector up to the fender apr0n connection.

There is one Splice and one connector between the eec plug in and the place at which the bk/lg wire terminates. an easy way to test without disconnecting the ground at the fender would be to hook up your test light to the pos side of the battery and then probe the bk/lg wire at the eec conn (dont have the relay plugged in. If the light comes on then the ground is good and you are correct,, the relay is fried.

Put your ohm meter across the relay coil, red/lg and bk/lg terminals,,, it should have continuity.

another possibility

Reply #2 – June 10, 2006, 08:33:06 PM

Ok I tested it using the power wire to the relay, the constant hot wire Black and Orange. Probing the black and green wire made the light on the test light come on.

Also I checked the coil on the relay with the multi meter set to ohms. it did move the needle but it didnt sweep but maybe a quarter of the way up on the RX10 setting on the RX1K setting it made it maybe half way up. so basically it has enough to move the needle but Im not exactly sure what its supposed to read.

I do know that placing a toggle switch in between the connectors for the power wires that the coil closes will start the car and make it run normally so it has to be something with that relay or the wiring to it.

I'll go out in a minute and double check again that it has power coming from the key.

another possibility

Reply #3 – June 11, 2006, 10:30:17 AM

here ya go,,,,,,

another possibility

Reply #4 – June 11, 2006, 08:35:32 PM

yeah thanks jcassity I picked one of those manuals up so now I can find the stuff Im having a bit of a time learning how to read all of it but Im gettin there with it. it doesnt show how to check alot of relays and such though which I was hoping it would mainly just the wiper switch and such. I even went through and laminated the wiring diagrams for the 5.0 so I dont mess them up to bad lol

Also the grounds good and its got power where its supposed to in the wires so its got to be the relay.

another possibility

Reply #5 – June 12, 2006, 12:24:34 PM

Your previous post up there shows you got some sort of manual to go by cause you kind of flipped a 180 on us here going from "WTF" to "exact pins and wire colors. Im glad you got an EVTM so now all you have to do is determine circuit priority and duplicate what is in the manual and make it happen in the engine bay.

ok,,,,,
first rule of thumb when reading schematics is to understand what they are trying to tell you about power applied and when its applied.

UNLESS OTHERWISE STATED, schematics illustrate componenets in thier "static" or de-energized state.

this means that if the contacts of a relay are showing as touching or not touching, then that is how the relay comes off the shelf.

____________EXAMPLE OF A NORMALLY OPEN RELAY_______
The coil>>>
set meter to ohms,,
one set of contacts will have continuity
the second set will read open (just like your eec relay illustration)
the coil should have continuity but the resistance should be atleast a couple or a few ohms. Usually the coil terminals are smaller than the contact terminals but this is not always the case. The terminals are numbered or lettered and by trial and error you locate the coil or use your schematics to verify. To energise the relay, use a DC power source and listen for the click. I made an old computer power supply my shop DC power source because it has several output ratings and is useful for bench testing things.

The contacts>>>
while you have the coil energized and the relay made a click sound , put your meter across the contacts and see if there is continuity. Release power to the coiil and you should loose continuity across the contacts.

The coil produces a magetic field and pulls the contacts together. when the electricty travels through a conductor that is wound up in tiny circles >ie the coil<, a magnetic field is produced. Take the outter top cover off the relay housing to see the inside workings of the relay.

remember,, schematics show parts in thier static state so if you need to verify operation,, you have to be prepared to simulate energized situations by being creative.

Some relays have a diode in parallel with the coil. its important to keep the relay energized when its it called upon and if there is any stray AC voltage running abround on your harness , the AC will cause the relay to click off and on. The diode prevents this as it only passes voltage in one direction or the positive stroke of the ac sine wave. This prevents the coils magnetic field from being sucked down due to the polarity shift of the negative stroke of the ac harmonic. You usually dont find the diode in a DC application but again, thats not allways the case and thats a longer story.

another possibility

Reply #6 – June 12, 2006, 07:01:22 PM

Yeah Im still learning it but I can pretty much tell what the wire connects to now and all. It's just still a little confusing because you have to skip from page to page and such. Like it says this wire continued on page 54 for instance. All the flipping back and forth is just a little distracting. Im getting there though slowly.

The part about the PC power supply is an idea I had never thought of that. I actually use a Ac/Dc adapter, the little cheap ones from walmart I think it ranges from like 3 to 12 volts. It's not enough to power the car but for checking relays and such it works great.
I plugged the relay into it and no click. there is a resistor looking thing in the bottom of the relay Im guessing it may be a diode as far as the terminals I found a neat trick.
well its not really a trick but its kind of neat. I had an extra harness out of a car that has most of the connectors that are on our cars on it. I cut the plugs off leaving a little bit of wire which is still color coded to the harness.

basically strip the ends off the wires and you can plug the sensor or relay or what be it you are testing into the plug that goes with it and make sure you get the power side to the power and ground side to ground this way. It's also easier to get the probes of my multi meter to touch the wires then it is to get it into the spots where the pr0ngs are for connecting to half the time.

Also you lost me on the last half with the sine wave stuff basically what I gathered is that if you have electric in the wrong spot its going to severely mess with the coil in the relay. Which that I do understand cause the coil is basically just a small electromagnet. I used to toy with those making tattoo guns and electric in the energy field really screws things up.