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Hello to all. I'm new to the forum so bare with me please. I have been in the process of turning my 66 Grumman into a food truck using the 97 F250hd crew cab as the chassis for the truck. I'm in year 4 and things are progressing nicely. Well as anyone knows there are always things that happen and that's the reason for me coming here. I have an electrical issue that I can not seem to get fixed. I'm looking for areas that I may have over looked or just missed altogether. The problem or problems (not sure they are related or not) is when the engine is running or just having the switch in the on position and I turn on the headlights the gauges drop to zero and the tach drops to zero plus the turn signal lights come on and stay on ( in the dash only). When I move the fuel tank select switch the same thing happens.
I have done a lot of modification to make this fit but I am using all of the 97 f250's wiring and sensors. I have gone over all the grounds and have checked and rechecked all plugs.
If anyone has ever come across this issue and could point me in the right direction that would be a great help.
So I'm at my wits end here and I could use a fresh idea as to where to look.
Pic of what it looks like so far.
It sound to me like a ground problem. On the F series there were ground points down by the kick panels for several things. Maybe one of these was overlooked.
It sound to me like a ground problem. On the F series there were ground points down by the kick panels for several things. Maybe one of these was overlooked.
Thanks for the reply.
I do not have any of the cab wiring harnesses just the dash harness and everything with that in the truck now. I did check the harness connector for that and I did ground the wires from that harness and I still have the same issues.
Grounds are what I thought all along but I have not found that to be the case. I check with a test light and I am getting a draw on the ground side of the dash so I believe it might be a relay or breaker. The truck has 249,000 plus miles and I had to replace the instrument cluster with a used one from Ebay (long story). At one time I everything worked so I've been chasing this for 2 weeks now.
I will most likely pull the harness out and go over it with a fine tooth comb before this is resolved.
Again thanks for the reply.
To add what Tom said there is also ground straps from body to frame and valve cover passenger side to body. There can never be enough grounds!
Thank you for reply.
I have all the grounds that you mention and I have 2 other grounds as well. The truck is grounded well. That's why I'm at my wits end about this. So my next step (unless someone has a better solution) I'm going to go through the whole harness and hopefully find the issue.
I'm still open to other options if anyone has an idea.
Thanks again for the reply.
Well as suspected the problem was a ground. The pink/orange strip wire and blk/light blue wire from cab harness needed to be grounded. After that was done and As I was letting the truck idle and I was verifying that the issue was resolved the engine started to studder and died. So far I have found out if I unground the pink/orange strip wire truck runs fine. So now I'm off to find a new problem. Any ideas would be appreciated.
Well I think the electrical problem is resolved but now I have another issue with the truck running. After much reading of threads on this forum I believe the issue is in the IDM circuit or uvch. When I have ohmed out the circuit I'll update my findings. Thanks for all the post from everyone about IDM circuit and harness checks.
Just a quick update to my issues. The UVCH was the problem. After replacing and rechecking ohms it fired right up. Idles smoother and seems a little quieter. I want thank everyone who contributes to this forum. It makes diagnosing issues with these older trucks a lot easier.
Well as it would seem I have another issue with electrical system on my 97 f250hd 7.3. After many weeks of trouble shooting I thought I had all fixed. Now My fuel select valve (it is new OEM part) is blowing the fuse every other time I switch from front to rear tank. I check all wiring to the valve and to the switch for shorts and all checked out. With the valve unplugged fuse does not blow. When plugged it pops as stated before. My question is why would a new valve pop a fuse? The tanks are new. The lines where flushed out. Could debree somehow cause it to pop fuses. My guess is yes but want your opinions. Thanks.
I'm with Glen on this. Check the wires to the senders on each tank for bare spots where they could touch metal. The fuse that powers the fuel tank selector also powers the fuel level senders.
Thanks for the replys. I have checked every inch of wiring throughout the build and I have rechecked the wiring after each issue comes up and nothing. I did remove the selector switch and found it to be clean. I did however find that the inlets where not working correctly. When in the rear selection air flows front to back not to pump. When in front selection flows correctly. Took valve apart everything seemed ok. Valve just doesn't open all the way. The only thing I haven't rechecked are the senders themselves in the tank. Everything was fine when I installed them in the new tanks so I'm not sure If I want to go that far right now. It's just odd that was working fine the one day nothing. This truck hasn't let the driveway but twice in 4 years. I start and run it daily. I'll update after I get new valve in. Thanks again for your input.
Well here's the update. After replacing the fuel select valve I got it to start an run. Now I have to cycle the key twice or let the key stay on for 30 seconds then it will start. I live in Florida and it's in The low 80s so not sure why this is needed. (I have replaced the UVCH and glow plugs 2 months ago). So I put in a new heavy duty relay that was suggested here and I still have this same issue. But wait there's more. Now I can not get my scan tool to stay connected. So more wire checking. I have constant power to pin 55, 71, 97 at the pcm. They pcm relay has constant power at all the right places. So my question is, is the pcm bad? Does it need to be reflashed or do I need to look elsewhere? Any help would be greatly appreciated.
I do own the correct wiring manual. So any suggestions on where to look and what to look for would be a big help. If anyone has this type of a problem with pcm and if having it replaced or flashed and it fixed the problem let me know and who and where did you go for the repair.
Thanks for your help.
I forgot to mention the truck seems to run just fine.
So I'm just trying to make sure I don't get stuck somewhere.
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