87 xj got a few ?'s

i'm running out of time to get my rig ready for this weekend.... i've got a few problems and was trying to get some quick advice, 1. the ignition switch is bad, if i wiggle the yellow wire going to it everything works fine but at time it goes dead, i have a new switch but was wondering if the switch would fix my problem. 2. sometimes the gauges dont seem to work right, especially the temp gauge, i was wondering if it would be a good idea to go ahead and put a mechanical gauge in? if so what works good for cheap and whats the best way to install. 3 last thing is i had the ac recharged, but instead of it blowing cold its just barely cool, thought it was probably caused from the heater core... thought about bypassing, but i wasn't sure if that would help... sorry for the long post, i have searched here and other places but thought someone might have a few quick answers before i get off work to try and get that fixed....

If you wiggle the wire, it's probably the connector or the wire that's bad. Try crimping the connector a little bit to get a snugger fit on the terminal. It's not clear whether a mechanical sending unit would have clearance inside the housing. If you have time to order a gage, try Summit, their's are very good price. For the AC, check if one of the AC lines going into the firewall is frosting up or at least feels very cold. If not, your AC just isn't working. Most people don't tell any difference whether the heater is hooked up or not. Late models run hot coolant through there all the time anyway. Maybe your blend door isn't moving. Check for the AC line going into the firewall. (Cold or not).

ac line are very cold, condensating and everything, i can hear something but cant tell if its actually moving the blend door or not, and the high side of the ac is so damn hot it will almost burn you thats why i thought it was getting to hot w/ the heater. i'm gonna just go ahead and bypass the heater. i bought some mechanical gauges last night, if i put the coolant temp probe in the stock sensor hole will it the bother the way the engine runs, or affect the auxilary fans? if so wheres the best place to it??? any im looking at the ignition switch tonight....

On the guage the OEM sending unit may be going bad or have a bad connection. I would try to replce that before going to the trouble of putting a mechanical guage in it's place. I agree with winter on the A/C. No opinion on the switch as I have no experience with a bad one.

IIRC, '87 has two temp sensors, one in the tstat hsg and one at the back of the head on the drivers side. One runs the gage, and one runs the computer. Not sure which. You should search for that info. Not sure about your fan. I think some of the older ones like yours (maybe) has a temp sensor for the fan in the radiator.

thanks, where does the wiring harness go to from the ign. switch? is it easily replaceable? or shoul i just try a new connector on the bad wire.... its old and the stock gauges don't really work the best so i got a 3 gauge panel that has volt meter, coolant temp, and oil pressure... i think that might be a bit more reliable, from what i read the rear is for the gauge and front is for engine, so i guess i could use the rear coolant temp sensor for my mechanical gauge... also what would be needed to put the aux. fan on a switch to run it constantly while trail riding?? i was thinking switch with relay, so i could leave it hooked up the factory way but also be able to overide it when needed.... anyone see any problems with this??

the two sensors for the '87 (assuming 4.0l) are:

1) rear of cyl head-- for temp gauge
2) left (driver) side of engine block, under exhaust manifoli-- CTS for ECU

and
P.S. how'd you get the name Shorty??

thanks...

cause i'm 6'8" just a nickname that stuck

gotcha-- I'm stuck with it (my last name)

Shorty said:

the two sensors for the '87 (assuming 4.0l) are:

1) rear of cyl head-- for temp gauge
2) left (driver) side of engine block, under exhaust manifoli-- CTS for ECU

and
P.S. how'd you get the name Shorty??

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If his 87 has a/c, would it have an aux fan? And if it has an aux fan, wouldn't that sensor be in the radiator?

yes has ac yes has mech fan and aux fan... where do i put coolant temp sensor for mechanical gauge....

joe_peters said:

If his 87 has a/c, would it have an aux fan? And if it has an aux fan, wouldn't that sensor be in the radiator?

Click to expand...

yes, also a third temp switch in radiator for cooling fan.

Shorty01GMC said:

yes has ac yes has mech fan and aux fan... where do i put coolant temp sensor for mechanical gauge....

Click to expand...

I don't know how much room there is in the passage at the back of the head, but if it doesn't fit there, I'd hit the salvage yard and get a water outlet/thermostat housing from one with the CTS in it and put it there.

X2 -- try back of head first

I know this is a couple weeks old, but, you stated the ignition switch is bad, that is the cause of your factory temp gauge failure, the ground for the circuit goes through the switch.