ScooterT20 Posted October 1, 2020 Share Posted October 1, 2020 Hello ladies, gentleman, them, they's....however you choose to introduce yourself, I have an '86 Comanche I purchased a few months back. I got it running and driving and even daily drove it for a few weeks. I currently have an issue with my instrument cluster. It's been a while since I have driven it but I was having issues with the oil pressure and tachometer. My tach pretty much just does what it wants and my oil pressure gauge will fluctuate when I turn the headlights on and adjust the brightness of my cluster. When I turn it up, the oil pressure goes up, when I turn it down, pressure goes down. I believe everything else is working as it should. I have quite a bit of mechanical experience so I'm just looking for a few places to start before I pull the cluster and check the wiring out. I did add a jumper ground from the bottom of the dash(the one that goes to plastic) to the left of the fuse panel. I'm thinking I likely have a ground issue. I have the full cluster. I'm not sure if this is a common issue you guys have seen. Link to comment Share on other sites More sharing options...
89 MJ Posted October 1, 2020 Share Posted October 1, 2020 You're luck that you even have a tach lol. I would start looking at grounds. I should probably take my own advice though and check the grounds for my gas gauge. I am not sure where the grounds are for that. I'm going to guess that @eaglescout526 or @Minuit would be able to point you in a general direction at least. Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 1, 2020 Share Posted October 1, 2020 Definitely start with the grounds. Check and clean them all and go from there. The early 84-86 clusters use old style connection for the gauges so taking the cluster out and looking at the contact prongs on the backs of the gauges and give them a good cleaning. The older clusters are notorious to have decently reliable gauges. Especially the tach. The tach likes to have a mind of its own. Link to comment Share on other sites More sharing options...
Pete M Posted October 1, 2020 Share Posted October 1, 2020 I fixed a lot of weird issues with my 88's dash by running a 10 ga wire directly from the negative battery terminal to the dash metal. if you haven't yet, you should accomplish all of Cruiser's MJ tips. it's one of the first threads in teh link in my signature. Link to comment Share on other sites More sharing options...
ScooterT20 Posted October 1, 2020 Author Share Posted October 1, 2020 1 hour ago, 89 MJ said: You're luck that you even have a tach lol. I would start looking at grounds. I should probably take my own advice though and check the grounds for my gas gauge. I am not sure where the grounds are for that. I'm going to guess that @eaglescout526 or @Minuit would be able to point you in a general direction at least. I know, I was pretty excite when I saw that in the for sale ad. I hate those useless dummy lights and the giant fuel gauge. I do have a 96 cluster I could use but the full 86 cluster is growing on me. Grounds is what I was thinking but from what I understand the cluster ground was the ground that I attached a jumper wire to the body. Should have cleared up some issues but no luck there. 52 minutes ago, eaglescout526 said: Definitely start with the grounds. Check and clean them all and go from there. The early 84-86 clusters use old style connection for the gauges so taking the cluster out and looking at the contact prongs on the backs of the gauges and give them a good cleaning. The older clusters are notorious to have decently reliable gauges. Especially the tach. The tach likes to have a mind of its own. I have a chiltons but the schematics are so small. I've also read a few of these pinned threads showing a few grounds but I was curious where the cluster ground is located. I though the ground I added a jumper to was the cluster ground but it made not difference. 49 minutes ago, Pete M said: I fixed a lot of weird issues with my 88's dash by running a 10 ga wire directly from the negative battery terminal to the dash metal. if you haven't yet, you should accomplish all of Cruiser's MJ tips. it's one of the first threads in the link in my signature. I might have to try that after I pull the dash and check the connections. I'm sure they're loaded with crud, my tail light bulb had 56 years of dried up dielectric grease in it. Wasn't difficult to scrape out but kind of crazy to see that old crap still in there. Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 1, 2020 Share Posted October 1, 2020 Just now, ScooterT20 said: I have a chiltons but the schematics are so small. I've also read a few of these pinned threads showing a few grounds but I was curious where the cluster ground is located. I though the ground I added a jumper to was the cluster ground but it made not difference. The electrical manual for 88 is on here. I do have an 86 manual that I can look over and provide assistance with. Sometimes that ground doesn't always help, but it may not help if the other grounds are dirty/bad. One ground from the battery to the block, on from the block to the firewall and then that's pretty much the grounds for everything else is that strap from the block to the firewall. Not sure where that strap is though on a 2.8L. Link to comment Share on other sites More sharing options...
ScooterT20 Posted October 1, 2020 Author Share Posted October 1, 2020 6 minutes ago, eaglescout526 said: The electrical manual for 88 is on here. I do have an 86 manual that I can look over and provide assistance with. Sometimes that ground doesn't always help, but it may not help if the other grounds are dirty/bad. One ground from the battery to the block, on from the block to the firewall and then that's pretty much the grounds for everything else is that strap from the block to the firewall. Not sure where that strap is though on a 2.8L. I was just reading that article about the grounds. I'll have to check the block to body and battery to block grounds. Sounds like it would be a good idea to add another ground from the battery to the radiator 10mm bolt. I was hoping there was an easily accessible ground I could check but we all know that's never the case. I'll have to unbolt the steering column and pull the cluster haha. Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 1, 2020 Share Posted October 1, 2020 Without pulling the cluster and stuff apart, its the ground that's bolted to the dash in cruisers tips is the cluster ground and everything else. If your truck has AC, youll benefit greatly if you do the blower ground mod as well. I know I saw an improvement in the volt gauge reading on my cluster. Link to comment Share on other sites More sharing options...
ScooterT20 Posted October 2, 2020 Author Share Posted October 2, 2020 17 hours ago, eaglescout526 said: Without pulling the cluster and stuff apart, its the ground that's bolted to the dash in cruisers tips is the cluster ground and everything else. If your truck has AC, youll benefit greatly if you do the blower ground mod as well. I know I saw an improvement in the volt gauge reading on my cluster. I don't think I have A/C but I'm sure that pulls some amps. You can never have too many grounds! I got my $200 XJ going last night. I plan to drive that for the winter so I can tinker with the Comanche. I'll probably pull it in and do the axle shaft U joints this weekend so I don't have to worry about the hubs exploding. There's basically no bearings left. Link to comment Share on other sites More sharing options...
Muncher Posted October 4, 2020 Share Posted October 4, 2020 On 10/1/2020 at 1:35 PM, eaglescout526 said: Definitely start with the grounds. Check and clean them all and go from there. The early 84-86 clusters use old style connection for the gauges so taking the cluster out and looking at the contact prongs on the backs of the gauges and give them a good cleaning. The older clusters are notorious to have decently reliable gauges. Especially the tach. The tach likes to have a mind of its own. Where are the grounds for the gauges ? Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 4, 2020 Share Posted October 4, 2020 2 hours ago, Muncher said: Where are the grounds for the gauges ? If you look up under the dash below the switch for the headlights, youll see a ground wire mounted there. Now that spot is notorious for looking rust colored and not being the best chassis to ground hook up. So thats why its recommended to take a better gauge wire and ground it out to the stud that holds the ebrake lever in place. Link to comment Share on other sites More sharing options...
Muncher Posted October 4, 2020 Share Posted October 4, 2020 18 hours ago, eaglescout526 said: If you look up under the dash below the switch for the headlights, youll see a ground wire mounted there. Now that spot is notorious for looking rust colored and not being the best chassis to ground hook up. So thats why its recommended to take a better gauge wire and ground it out to the stud that holds the ebrake lever in place. Alright. Is that the ground for all the gauges? Also what gauge wire would you recommend I'm not the best with wire Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 4, 2020 Share Posted October 4, 2020 Thats the ground for the entire cluster, gauges and all. Look at Cruisers tips. He has a recommended gauge wire. I used some sort of I want to say a higher gauge high quality copper speaker wire my dad had laying around and used that for the ground extension. Link to comment Share on other sites More sharing options...
Muncher Posted October 4, 2020 Share Posted October 4, 2020 Just now, eaglescout526 said: Thats the ground for the entire cluster, gauges and all. Look at Cruisers tips. He has a recommended gauge wire. I used some sort of I want to say a higher gauge high quality copper speaker wire my dad had laying around and used that for the ground extension. Alright thanks. Where can I find cruiser tips? Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 4, 2020 Share Posted October 4, 2020 Main MJ tech forum and Pete has them in his signature or google Cruiser54 and you should find his main website. Link to comment Share on other sites More sharing options...
jdog Posted October 5, 2020 Share Posted October 5, 2020 54 minutes ago, Muncher said: Alright thanks. Where can I find cruiser tips? link in my signature or.... http://cruiser54.com/ Link to comment Share on other sites More sharing options...
Muncher Posted October 5, 2020 Share Posted October 5, 2020 1 minute ago, jdog said: link in my signature or.... http://cruiser54.com/ Thank you I found a good article on there about changing the blower motor and fan which i will try and see if its the problem. Even if its not seems like a good thing to do anyways Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now