97 grand cherokee hooked battery cables up wrong jump starting

[borninabarn]

yes I know I screwed up after doing this 10000 times.Well the battery was down in my 1997 jeep 5.2 grand cherokee limited so I hooked up the jumper cables to the jeep right but on the car I was using to jumpstart the jeep I had the positive and negetive turned around for about 10 seconds until I realized I did.Now on the jeep it turns over ok but wont fire.All of my gages wont move and my radio doesnt work.I checked every fuse in the box under the hood and they are all good also checked every fuse on the passenger kick panel and those are all good.I dont know how to check the bigger 25 amp aluminum fuses or the relays (black ones in the fuse boxes)and dont know if those have anything to do with my problem??On one site they say there is a 3rd fuse box on a 1997 but I dont know where it would be if there is one?I tryed hooking the positive and negitive cables together over night(some say it clears the computor)that didnt do anything.Any dodge techs out there that might know what I should check and how to check whatever could have happend?In my book it shows there is a fuse for the amplifier and gages but I checked that one on the kick panel and it is ok.Any help would be great!Thanks,Born

[DIVERHERB]

There is no third fuse block. There are alot of things on a efi car that could be messed up from hooking the battery up backwards. But the first thing I would check is the battery, If it was dead then it is possible that you just finished off the job by hooking it up backwards. After assuring a good battery then it is a matter of running out the main feed to see if there is current to the pdc (fuse block under the hood). That is where I would start if there is nothing on the jeep working. I have seen reversed battery's take out alot of pcm's but never entire systems, but it could happen.

[borninabarn]

Thanks so much for helping try and solve this problem!I do have power to the PDC.The Jeep turns over but does not fire.The fuel gage,amp gage do not work the oil pressure gauge seems to move a little when turning the ignition on.The warning center works But the radio does not work any more? I checked all the fuses again they are ok like I said before not sure how to check the small black relays and if they have to do with this or not?On the fuse application guide it show a fuse that runs the radio amplifier and the cluster but I thought I had checked everyone.Is there any fusible links anywhere I should be looking at?I am just not sure what to do next?Times are tough right now for the Family or else I would take it to a shop.We really need the Jeep for transportation.Thanks for your time.Born

[DIVERHERB]

This may sound pretty basic but before we can go anywhere I have questions. Is there spark at plugs? if not is it at the coil? There is a test port on the fuel rail that looks like a tire valve, when you depress it do you get a pretty decent spray of fuel while the engine is cranking? Is your car equiped with factory alarm system? And did you check the fuses on the inside panel (alot forget about these). Is there anything else that does not work, i.e. headlights, windows, seats, turn signals. The reason I ask this is that the body control module is not as resistant to shorts as the pcm is. Let me know and I will try to help, but something like this is easier to test if you have the DRB to hook up and see what is not coming on line.

[borninabarn]

Ok here is where I am at.The Volt Gauge and Gas Gauge do not work(The Radio DOES WORK) and everthing thing else except those gauges and no spark. I hooked up my spark tester to a wire turned it over No Spark.I could not find the connect on the rail I know what you are talking about on that.Headlamps work.power locks work,seats work,turn signals work,windows work and it does have the factory alarm.Thats all I could do tonight dark snowing and wife is gone now.Where is the BCM? iS THAT THE ONE ON THE PASSENGER STRUT TOWER?I really do thank you for your help! Kurt

[DIVERHERB]

The BCM is located inside the car. The pcm if located passenger side up against the firewall. I think that is what you are seeing. Anyway if you are sure that you have checked all fuses and all are good. There is a ASD relay in the pdc, the location will be marked on the cover of the pdc, it signals the pcm for spark control and fuel pump. You can try swapping this relay with another (anyone but the fuel relay), and see if it will start. But I think after your last post about what is actually not working I think that you pcm is gone. along with running you fuel/ignition system it controls your fuel guage and volt guage also. If you could get ahold of a code reader I would bet that there is a code for ccd bus or a no response fault. Sorry.

[borninabarn]

Hello Back Again! Well went and bought a used known good computor plugged it in and still nothing? Still the same everything.I tryed getting the code by turning on the ignition till the miles came on turned on an off 4 times and the miles just come up again.With my old computor it worked once but the sun was hitting the dash and I couldnt read the 2 numbers I thought they were 38 and 18?are there any fusible links that I should be looking for? Also when you talk of changing out 2 relays are you talking about the asd relay in the fuse box under the hood or?Any of the relays in the kick panel have anything to do with my problem maybe?I am stuck everyone.Thanks for your time

[borninabarn]

FIXED!!!!!!!!!!!!!!!!!! Thanks for helping me out guys!!!! I really feel kind of stupid again oh well taking morphine everyday for my back problem.But I went again and checked every fuse again and one mini 20amp that was in the fuse block under the hood didnt light up on one side testing it,It looked good and i couldnt see where the metal tab had broke inside but it sure was bad!! bought a new one put in the gauges moved like they should and I turned the key after 3 months and it started right up!nice to have my Jeep back in this snowy Iowa weather!!Thanks Again!!

[Colts19]

Originally Posted by borninabarn

FIXED!!!!!!!!!!!!!!!!!! Thanks for helping me out guys!!!! I really feel kind of stupid again oh well taking morphine everyday for my back problem.But I went again and checked every fuse again and one mini 20amp that was in the fuse block under the hood didnt light up on one side testing it,It looked good and i couldnt see where the metal tab had broke inside but it sure was bad!! bought a new one put in the gauges moved like they should and I turned the key after 3 months and it started right up!nice to have my Jeep back in this snowy Iowa weather!!Thanks Again!!

Borninabarn,

I wanted to thank you for making your posts... I fixed my problem with your solution in a matter of minutes because of your post you made a couple of years ago. Thanks!!