1996 Ford F 150 4.9 L6

Three amps on that relay control wire? borntoroll is right, that does sound abnormally high. If that relay coil is shorted, then it'd certainly explain a failed driver. But not the other inoperative components.

Are there any other similar relays that you could borrow from another system? Mostly I'm interested in comparing the current draw of the fuel pump relay compared to another. If they're both three amps, then I guess that's normal. If it's significantly less, then I'd say that relay is bad.

Do you have a scanner available? If all those outputs are dead, then I'd suggest running the KOEO and KOER self-test, and see what codes you get back. Those tests will force the PCM to use all it's outputs, and should flag codes for inoperative stuff.

i do not have a scanner im just a poor DIYER IM SO SORRY

I did get the short in fuse 16 fixed tho ome less problem to deal with YES FUSE 16 IS A FIX YEA/

i switched relays with the trailer relay in the underhood relay retested current is now 300 milliamp i bought a new relay and retested again is same about 300 milliamp // second confirmed FIX FIX FIX AND AGAIN THANKS FOR ALL YOUR ASSISTANCE TO EVERYONE HERE

it looks to me like the U 20A fuse sends power to the PCM Power relay on the R/LG wire in the start/run position. That closes the relay and sends power to PCM and fuel pump relay. Meaning the red is power so the LB/O is ground. So if you put the key in just the RUN (without starting the truck) position you should be getting 12V to the red wire on the fuel pump relay. If the fuel pump relay is NOT being turned on then the 12V should be just flowing through the coil and down the LB/O wire. So Im thinking that if you put the key in the RUN position then you should be able to measure 12v on the LB/O wire at the fuel pump relay. Then measure that same wire at the PCM. if you don't see 12V or anything less than 12V you know you have a break in the wire or corrosion. Could there be corrosion at the Test conn pin 6?

THIS IS THE ONLY PROBLEM I STILL HAVE/// the LB/O GOING INTO THE PCM is the dead wIre so i ran the GROUND from where that LB/O was supposed to be / left the LB/O COMPLETELY DISCONNECTED AND TAPED UNSIDE THE BOTTOM OF THE FUSEBLOCK GROUNDED THE RELAY AND IT NOW RUNS LIKE A SCALDED DOG LOL neither o2 sensor works heater circuits are good and have no grounds to any of the 3 soolenoids on the back right side of the valve cover

THIS IS MORE LIKE A LONG LONG CASE STUYDY NO SIMPLE FIX

toadyboy1957 wrote: i switched relays with the trailer relay in the underhood relay retested current is now 300 milliamp i bought a new relay and retested again is same about 300 milliamp // second confirmed FIX FIX FIX AND AGAIN THANKS FOR ALL YOUR ASSISTANCE TO EVERYONE HERE

Sweet! :woohoo: Dare I say we're getting somewhere?

I think the shorted relay probably accounts the cooked fuel pump relay driver. You could remove the PCM and look for burned components on the circuit board, but I think a replacement PCM would be the better way to go.

The other outputs that don't work may require more testing to verify. No worries about not having a scanner, sir. Just trying to think of ways to make the job easier.

That's what I was getting to also with what I said. If he can verify it is a bad driver for the fuel pump relay then he can get a new pcm. I would verify one problem before I move to the next. Maybe the new pcm (if he needs one) would also fix the other problems

AS FAR AS THE O2 SENSORS GO THE HEATER CIRCUITS HAVE BEEN CHECKED FOR SIGNAL FROM THE PCM ALL IS GOOD THERE THE 12 VOLTS TO THE O2 SENSORS ALSO VERIFIED GOOD THE ONLY THING MISSING IS THE GROUNDS FOR THE O2 SENSORS THE SWITCHED SOLENOIDS ON THE VALVE COVER ALSO HAVE NO GROUNDS BUT I CAN PROVIDE THOSE GROUNDS WITH 1 WIRE THAT IS NO PROBLEM DONT KNOW HOW LONG THOSE HAVE HAD NO GROUNDS

what would happen if i ran a ground to the PCM from the O2 SENSOR

You said in an earlier post that you had a good ground on 1 or 2 pins at the pcm but not a good ground and a few other pins? Correct?
But one of those good grounds going to the pcm is spliced into those other grounds that are not good according to the diagram? Correct?

If you are sure you are missing grounds to the pcm I would stay on that path and not worry about all the other things. This is only my opinion.
According to your post, you have a good ground at pin 103. But you don't have good grounds at pins 24, 51, 76 or 77. All of these grounds go to the same location G101. The grounds coming off of pins 24 and 51 splice into the ground wire coming from pin 76 before they go to G101.
I would be trying to figure out why you don't have good grounds on those pins. If you don't have all your grounds to your pcm it can make it do or NOT do weird things. This is not hard to do. Check out ScannerDanner's video, its a no communication video on a Toyota. He explains perfectly how you should check them.
In my opinion, if you have verified that you have bad grounds at the pcm its kinda of pointless to be going after other problems at this point.

IN my earlier post i Had only checked and verified 1 of the grounds//// SINCE THEN ALL GROUNDS have been backprobed and verified GOOD AT THE PCM

reading through everything is there anything else i need to test or do brfore condemning this PCM??

Did you all get busy or did you get mad at me for being so slow lol all i wanted to knowis THERE ANYTHING ELSE I NEED TO CHECK OR TEST ?? PLEASE ANSWER SORRY FOR NOT BEING A TOP NOTCH DIAGN OSTICIAN ..

Hey if all your inputs are good then as mentioned before it sounds like your relay may have taken out your fuel pump driver in your ECM I'm not sure your testing your 02 and other sensor grounds correctly though

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All grounds checked using 12 volt test light to battery posotive i have done resistance checks of all 3 O2 sensors on the heater circuits and each have 12 volt ecm feed but no grounds to any of the O2 sensors or any grounds to the TREE SOLENOIDS // THE EGR SOLENOID,,and other 2 solenoids on the valve civer as ive explained in my earlier posts

toadyboy1957 wrote: Did you all get busy or did you get mad at me for being so slow lol all i wanted to knowis THERE ANYTHING ELSE I NEED TO CHECK OR TEST ?? PLEASE ANSWER SORRY FOR NOT BEING A TOP NOTCH DIAGN OSTICIAN ..

Sorry sir, didn't meant to leave you hanging! I'm with Ben, it sure sounds like the fuel pump relay driver got smoked by the relay. If you're confident in your power and ground testing, then I think it's PCM time.

I think it's reasonable to wait on the O2 and solenoid issues until after you do the PCM. The problems with those outputs may be related, and might get taken care of along with the fuel pump relay issue. If not, then we can attack them like normal.

so is there anything else i need to check and does it sound like ive checked and tested everything like i should have or is there some other technique for testing what i have and thanks tyler and ben for your helpfullness