Problems today.

[CEThomas]

Well we went to start the 4.0 today for the first time after the swap. And we are running into problems :headpop:

 

First on the lights: Pull the lights on and the marker lights come on but no low or high beam head lights :nuts: But have flash to pass lights when we pull the handle :nuts:

 

Second problem is no power to the fuel pump. Have 12 volts of power at the relay but less then 1/2 a volt at the plug under the dash going to the pump. I ran hot wire to the pump and it starts and will run OK :mad:

 

 

Third problem is the gas tank sending unit is a 89 and my dash and wiring is out of a 93. Any way around this as the XJ sending unit will not mount on the MJ cage :nuts:

 

 

Any ideals on what I should look at?

[Eagle]

Third problem is the gas tank sending unit is a 89 and my dash and wiring is out of a 93. Any way around this as the XJ sending unit will not mount on the MJ cage

Pull the fuel pump/sender assembly. Remove the two wires from the sender (they should be slip-on spade terminals) and reverse them. Reassemble.

[CEThomas]

OK

[MiNi Beast]

I would like to know about the lights too. I've been running a toggle switch for my head lights. I got all the same syptoms and itm sucks. Been tryin to figure it out. Was your light switch good before? Mine Was always like that once I got truck. Easier to figure out problem if everything worked correctly before.

[CEThomas]

I am not sure but I think it was. It was out of a doner and I did not check it.

[JOMJ87]

I would start with checking the switch and all the connections to it. Its sounds like the wires arent getting juice right. Or maybe a ground somewhere that isnt very good. Thats just my first ideas.

 

Cole

[Eagle]

Dummy me! If you haven't yet done what that idiot Eagle suggested below -- DON'T.

 

Third problem is the gas tank sending unit is a 89 and my dash and wiring is out of a 93. Any way around this as the XJ sending unit will not mount on the MJ cage

Pull the fuel pump/sender assembly. Remove the two wires from the sender (they should be slip-on spade terminals) and reverse them. Reassemble.

 

I was thinking about this last night as I drove the wife to dinner. The fuel tank sending unit is nothing but an in-line variable resistor. Reversing the terminals will do NOTHING to correct for the fact that Chrysler chnged the polarity of the gauges from 1990 to 1991. Does the gas gauge work at all? If so, what does it do?

 

Try this -- first, unplug the connector for the fuel pump and sender -- it's in the wiring harness about a foot or 18 inches from the tank. Turn on the ignition and see where the fuel needle points (it should either on 'E' or on 'F'). Then go to that connector you unplugged. On the body side of the connector, jumper the fuel gauge power wire (the thin, colored wire -- the heavy one is for the fuel pump) to the ground. Then turn on the ignition and see where the needle points.

 

Let me know what you find.

[CEThomas]

Dummy me! If you haven't yet done what that idiot Eagle suggested below -- DON'T.

 

I was thinking about this last night as I drove the wife to dinner. The fuel tank sending unit is nothing but an in-line variable resistor. Reversing the terminals will do NOTHING to correct for the fact that Chrysler chnged the polarity of the gauges from 1990 to 1991. Does the gas gauge work at all? If so, what does it do?

 

Try this -- first, unplug the connector for the fuel pump and sender -- it's in the wiring harness about a foot or 18 inches from the tank. Turn on the ignition and see where the fuel needle points (it should either on 'E' or on 'F'). Then go to that connector you unplugged. On the body side of the connector, jumper the fuel gauge power wire (the thin, colored wire -- the heavy one is for the fuel pump) to the ground. Then turn on the ignition and see where the needle points.

 

Let me know what you find.

 

 

 

Kind of found that out today after I pulled the sending unit / pump :oops: The fuel gauge is working backwards, It's reading 3/4 tank when it should show 1/4. I will try the jumper and see what I get.