socal1200r Posted January 12, 2010 Share Posted January 12, 2010 Went to the local Jeep dealer today, and asked them if the water temp and oil pressure sending units for gauges were the same for a 4-cyl and 6-cyl, and he said they are. Even showed me the parts picture on the computer screen, and they listed the same part numbers for either engine. So it looks like my gauge cluster swap is complete, and I'll just have to get used to the water temp and oil pressure readings being on the "high" side for now... Link to comment Share on other sites More sharing options...
dasbrick Posted January 12, 2010 Share Posted January 12, 2010 if i switch an 87 half cluster to an 87's full cluster do i still need to replace the sending units? Link to comment Share on other sites More sharing options...
socal1200r Posted January 12, 2010 Share Posted January 12, 2010 if i switch an 87 half cluster to an 87's full cluster do i still need to replace the sending units? Yes, even if the gauge clusters are from the same engines, because the half cluster uses sending units for warning lights, not gauges. So you'll have to replace the warning light sending units with gauge sending units. If you read thru this thread, you should be able to get the part numbers for the oil pressure sending unit and water temp sending unit. Hang on, here's the info: Oil pressure sending unit for a gauge: Duralast PS133, $20 at Auto Zone Water temp sending unit for a gauge: BWD WT761, $19 at Advance Auto Do NOT use Duralast TU108 for the water temp sending unit, even though it's listed in that NAXJA how-to thread, because I used one and it doesn't work (I believe it's for a warning light, not a gauge). Since my full gauge cluster came out of an '87 XJ 6-cyl, and my MJ is an '88 4-cyl, these should be the exact same sending units you'll need for your '87 full cluster. Good luck, and the full gauge cluster is SO much nicer than the half cluster. Before you make the swap, and you have the full gauge cluster, you might want to consider putting on white face gauges, and/or replacing the bulbs with LEDs. I was going to replace the gauge illumination bulbs with red LEDs, and use white LEDs for the turn signals and high beam indicator, but luckily no place around here had all the bulbs I needed (9 red and 3 white). But the regular white bulbs seem to light it up just fine... Link to comment Share on other sites More sharing options...
dasbrick Posted January 12, 2010 Share Posted January 12, 2010 they make LED bulbs for the instrument size? wow! will do, thanks for the translation Link to comment Share on other sites More sharing options...
socal1200r Posted January 12, 2010 Share Posted January 12, 2010 they make LED bulbs for the instrument size? wow! will do, thanks for the translation Yup, the bulb size you're looking for is 194. The idiot lights in the piece to the left of the gauge cluster, for the brake, seat belt, upshift, etc., are smaller, so I didn't check on those, since they're rarely on anyway. Here's a link to a seller on eBay that has the 194 wedge-base LED bulbs for the gauge cluster. I was going to get 9 of the red 4-bulb LEDs, and 3 of the white 1-bulb inverted cone LEDs for the turn signals and high beam indicator, but decided not to do it. I didn't want to wait to get the bulbs before swapping the gauge clusters. The local auto parts stores had some of the 4-bulb 194s in red, but they were almost $11 for two, where this guy is selling them for less than $4 for two. http://stores.ebay.com/U2-LEDS__W0QQ_fsubZ20691755 But if you're not in a hurry, I say go for it on the LED bulbs. I would've spent about $24 plus shipping to do the red/white bulb mix like I wanted. And I think it would've looked kinda cool, having that red glow on the gauges at night, with the green turn signals and blue high beam indicator being much brighter with a white LED shining down on them. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 12, 2010 Share Posted January 12, 2010 Another thing about using LEDs for an application that will be dimmed by a rheostat (like dash lights) - sometimes they don't work well. They simply click off and on and don't gradually dim like the incandescents if they don't have a built-in ballast resistor. Make sure before you buy that the LEDs will work on a variable voltage circuit. :cheers: Link to comment Share on other sites More sharing options...
socal1200r Posted January 13, 2010 Share Posted January 13, 2010 Another thing about using LEDs for an application that will be dimmed by a rheostat (like dash lights) - sometimes they don't work well. They simply click off and on and don't gradually dim like the incandescents if they don't have a built-in ballast resistor. Make sure before you buy that the LEDs will work on a variable voltage circuit. :cheers: Good point...knowing my luck, I would've bought all those LED bulbs, and they wouldn't have worked correctly. Personally, I run with my dash lights at their brightest setting anyway, so the LEDs being all the way on or off, with no dimmer capability, wouldn't have been an issue. I just checked the red 4-bulb LED on that eBay sight, and it says it has an operational range of 10.5v to 15.8v, so maybe they'll dim? I know on my motorcycle, if I put LED bulbs in the front and rear turn signals and brake light, they wouldn't work at all. If I ran just LEDs for the rear turn signals and brake light, they'd work, but blink faster than normal. Apparently, to make all the LEDs work properly in that application, I needed some kind of load equalizer gizmo. I have no skills at automotive electrics, so I just put amber incandescent bulbs in for the turn signals, and left the red LED bulb for the tail light. But I still think red gauge lights would look pretty cool, a la BMW, lol... Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 13, 2010 Share Posted January 13, 2010 I just checked the red 4-bulb LED on that eBay sight, and it says it has an operational range of 10.5v to 15.8v, so maybe they'll dim? Yes, with with those operating votages the Ebay LEDs will dim until about half rotation of the dimming rheostat (if the rheostat isn't corroded thus reducing it's slider output voltage), then they will go out. I'll stick with my incandescents. Any corrosion at all in the dimmer rheostat will reduce voltage to the dash lights so the LEDs may not work at all. Link to comment Share on other sites More sharing options...
dasbrick Posted January 14, 2010 Share Posted January 14, 2010 Where's the rheostat located in relation to the dash lights. might just replace that at the same time? Link to comment Share on other sites More sharing options...
socal1200r Posted January 14, 2010 Share Posted January 14, 2010 Where's the rheostat located in relation to the dash lights. might just replace that at the same time? Isn't the "rheostat" the same thing as what the dash light dimmer knob does? If not, then you know why I'm no automotive electrics genius, lol... Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 14, 2010 Share Posted January 14, 2010 Isn't the "rheostat" the same thing as what the dash light dimmer knob does? If not, then you know why I'm no automotive electrics genius, lol... A rheostat is a potentiometer (variable resistor) that raises or lowers the voltage to a load. Rotating the headlight switch knob controls the rheostat and the dash lights are the load in this case. :cheers: Link to comment Share on other sites More sharing options...
dasbrick Posted January 14, 2010 Share Posted January 14, 2010 Oh well sweet, I'm getting a new one here soon to replace my busted headlight switch housing then... lol. Link to comment Share on other sites More sharing options...
Grant Posted January 2, 2011 Share Posted January 2, 2011 Trying to figure out why tach reads double? My 86 2.5l tack is way wrong. What should I be looking for to set it correctly? Link to comment Share on other sites More sharing options...
tbrand Posted January 2, 2011 Share Posted January 2, 2011 I knew I should have done the HO swap. :fs1: Yeah, but then you would have had the fuel gauge polarity/accuracy problem unless you could find an MJ HO sender. And those are tough to find - only for two years were they made........... What if I have a HO XJ sender? I have a spare HO XJ in my shop that I am going to strip down for the MJ. I believe the MJ and the XJ are opposites - the XJ would read full at the same resistance as the MJ would read empty. Link to comment Share on other sites More sharing options...
Automan2164 Posted January 2, 2011 Share Posted January 2, 2011 I knew I should have done the HO swap. :fs1: Yeah, but then you would have had the fuel gauge polarity/accuracy problem unless you could find an MJ HO sender. And those are tough to find - only for two years were they made........... What if I have a HO XJ sender? I have a spare HO XJ in my shop that I am going to strip down for the MJ. I believe the MJ and the XJ are opposites - the XJ would read full at the same resistance as the MJ would read empty. Incorrect. The MJ and XJ will read the same, but will not interchange due to differences in the tanks. The opposites that you are referring to is present in Renix vs. H.O. Rob L. Link to comment Share on other sites More sharing options...
tbrand Posted January 2, 2011 Share Posted January 2, 2011 Aha. Thanks for the clarification. Link to comment Share on other sites More sharing options...
Grant Posted January 3, 2011 Share Posted January 3, 2011 I believe this is the origional dash in the vehicle too? What would have caused this? Trying to figure out why tach reads double?My 86 2.5l tack is way wrong. What should I be looking for to set it correctly? Link to comment Share on other sites More sharing options...
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