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1990 electircal issues.

H

Hardrock2401

NAXJA Forum User
Location
Illinois
I recently dipped into the xj world and got a 1990. After doing almost everything I have read, I have fixed most of my "renix" issues, runs like a champ....but have two weird electrical issues.

1. Turn signals only work when completely stopped, or if my headlights are off. If I'm driving with my headlights on, they don't work. But will work when my headlights are on and to 100% complete stop.

2. My head unit works perfect when stopped.....but when driving and I let off the gas, the stereo shuts off lol. Every time I give the truck gas and let off real fast only the indash shuts off.


Any help on these issues would be greatly appreciated.
 
Try turning your key slightly like you are trying to start it, not enough to engage the starter, but to wiggle the mechanism. Sounds like my 94 that needed a new ignition switch. I would lose fan, wipers, turn signals, and radio. No idea on the lights.
 
Last edited:
Hardrock2401 said:
1. Turn signals only work when completely stopped, or if my headlights are off. If I'm driving with my headlights on, they don't work. But will work when my headlights are off driving and to 100% complete stop.
Click to expand...

Can't figure out how to edit. But I meant when the headlights are off and driving, they work.
 
i would suspect a ground issue. do the hazard lights work when your driving?

and also does stopped imply having your foot on the brake peddle? or in park with no one in it.
 
Hardrock2401 said:
I recently dipped into the xj world and got a 1990. After doing almost everything I have read, I have fixed most of my "renix" issues, runs like a champ....but have two weird electrical issues.

1. Turn signals only work when completely stopped, or if my headlights are off. If I'm driving with my headlights on, they don't work. But will work when my headlights are on and to 100% complete stop.

2. My head unit works perfect when stopped.....but when driving and I let off the gas, the stereo shuts off lol. Every time I give the truck gas and let off real fast only the indash shuts off.


Any help on these issues would be greatly appreciated.
Click to expand...

I had similar issues with my '90XJ and have most of them resolved. I believe that the issues related to grounding problems but after doing everything I read on this site (refreshed all the grounds, cleaned the mounting points and upgraded all my cables with a heavy duty set Old_man recommended) but even with all this I couldn't get them to go away. Here is what I did:

1) All the fixes above - got better but the radio would still cut out.

2) Installed a kit that moves the control point for the headlights to a set of relays close to the battery. (kit similar to the one at this site: https://www.amazon.com/Headlight-Relay-Wiring-Harness-Ceramic/dp/B00H5JFHR0) - This removed a HUGE source of power draw from in the cabin to the battery area and helped a lot but the head unit would now only reset when I turned on the turn signals

3) Replaced the turn signal flasher with a digital one and changed all the front turn signal bulbs to LED (big ones under the headlight as well as the side markers).

I haven't had the radio cut out since doing all this. My best guess is that with the poor grounds coupled with an undersized power feed to the fuse box, an aging XJ simply overpowers the circuit so by going to lower current bulbs and moving the headlight function directly to the battery, it removed enough of the power draw so that everything works perfectly.

One note, I originally tried changing the turn signal bulbs in the rear to LED as well but with all the front/rear changed, the current draw was too small to trigger the relay so I moved the rear back to normal bulbs.

HTH
Todd
 
there is a ground up under the dash that everything grounds through. i myself have not looked for it but that could be the culprit if you have not already fixed it.
 
Have not checked my hazards. I have extra grounds all over the place under the hood, as well as the underdash ground. It works with the brake pushed or not at a stand still. Though I have not checked the actual bulb sockets for grounds which I guess should be my next check.

Stereo side I will add a ground and see if that clears up anything.
 
Check your alternator output while you are at it. One of the blessings of the RENIX system is the ECU does not regulate the voltage output.
 
Hypoid said:
Check your alternator output while you are at it. One of the blessings of the RENIX system is the ECU does not regulate the voltage output.
Click to expand...

Voltage while at idle is 14v+, checking with a good mulitmeter, gauge never moves from 9v in the cluster. Given I cant hold the multimeter under the hood while driving, I could not tell you whether it is any different while driving.
 
i would have to suspect its a ground issue. mine starts at 14v and the gauge slowly dips the longer its running. i suspect i have a ground that increases resistance as it warms up.
 
My '90 just started doing a similar thing. Starts up at about 13V and drops down into the red zone the longer I drive. battery seems to be doing fine though as it starts fine. Were you guys able to nail down the cause of this? I don't want to chase electrical demons through the engine compartment if you've already figured it out.
 
90cherk said:
My '90 just started doing a similar thing. Starts up at about 13V and drops down into the red zone the longer I drive. battery seems to be doing fine though as it starts fine. Were you guys able to nail down the cause of this? I don't want to chase electrical demons through the engine compartment if you've already figured it out.
Click to expand...

Just test it.

There's no silver bullet cure like you are seeking.
 
Unless you installed it, there is no easy way to know how old your alternator is so having it tested is a good idea.

FWIW, my '90XJ was MUCH better after the fixes below but it now operates perfectly. Turns out I had a couple of culprits causing issues. First, the alternator was pretty much shot and I wouldn't be surprised if it was original to the XJ (198,000 miles). It wasn't charging very well and if I left the XJ for more than a week without a battery tender, it would crank very slowly.

My first thought was battery but after putting a new one in, the problem didn't go away. Next step, change the alternator. This was a step in the right direction but I would still see slow cranking if I left it for a couple of days and still had the electrical gremlins. The final step was to replace the starter and now the old girl is acting like it is brand new again. Again, I wouldn't be surprised to find that this was the original starter but after these two changes, it cranks at twice the speed (at least it feels like it) starts like a dream, runs great and exhibits none of the electrical gremlins I had prior. Recently, I left it sitting in the garage for 4 weeks without the battery tender and when I went to start it, it not only fired right up but the alternator gauge didn't move beyond the normal range.

XJ's have a reputation for being tough and I wonder some times if I take this for granted. On most other cars, i would have started by changing the alternator and upon seeing slow cranking would have jumped in to replace the starter. There is so much bad press on the Renix electronics that I jumped to the (incorrect) assumption that my problems were inherent to the design. To be fair, I had already performed EVERY maintenance item that Cruiser has posted to this (and other) forums including refreshing all grounds and even upgrading the battery leads with a custom set from Jon Kelley. Lesson learned here: when all else fails, go back to the basics...
 
Last edited:
tjmotter said:
Unless you installed it, there is no easy way to know how old your alternator is so having it tested is a good idea.

FWIW, my '90XJ was MUCH better after the fixes below but it now operates perfectly. Turns out I had a couple of culprits causing issues. First, the alternator was pretty much shot and I wouldn't be surprised if it was original to the XJ (198,000 miles). It wasn't charging very well and if I left the XJ for more than a week without a battery tender, it would crank very slowly.

My first thought was battery but after putting a new one in, the problem didn't go away. Next step, change the alternator. This was a step in the right direction but I would still see slow cranking if I left it for a couple of days and still had the electrical gremlins. The final step was to replace the starter and now the old girl is acting like it is brand new again. Again, I wouldn't be surprised to find that this was the original starter but after these two changes, it cranks at twice the speed (at least it feels like it) starts like a dream, runs great and exhibits none of the electrical gremlins I had prior. Recently, I left it sitting in the garage for 4 weeks without the battery tender and when I went to start it, it not only fired right up but the alternator gauge didn't move beyond the normal range.

XJ's have a reputation for being tough and I wonder some times if I take this for granted. On most other cars, i would have started by changing the alternator and upon seeing slow cranking would have jumped in to replace the starter. There is so much bad press on the Renix electronics that I jumped to the (incorrect) assumption that my problems were inherent to the design. To be fair, I had already performed EVERY maintenance item that Cruiser has posted to this (and other) forums including refreshing all grounds and even upgrading the battery leads with a custom set from Jon Kelley. Lesson learned here: when all else fails, go back to the basics...
Click to expand...

Yup.
 
When you say "test it" what "it" are you referring to the grounding screw?

I'm not looking for a silver bullet, just the most likely place to start troubleshooting. If a fix has worked for others on this forum then I'm starting with the odds it will also work for me. I'm just trying to tap the wealth of knowledge and experience on this forum and make my weekend a little longer by not wasting time chasing an issue that's not there.
 
IIRC the turn signals, the radio, the WS Wipers, and AC blower all pull power from one undersized brown wire from the fuse box to the ignition switch that fries the Ign switch and the connector assy/wires, and the fuse holder connections. It also fries the wiring and Blower switch, all the way to the blower resistor pack and the HVAC blower. My 85 was the worst, the 87 almost as bad, the 89 has mostly fired the head light switches and wiring. But I would start there at the ignition switch and that brown wire

.
Hardrock2401 said:
I recently dipped into the xj world and got a 1990. After doing almost everything I have read, I have fixed most of my "renix" issues, runs like a champ....but have two weird electrical issues.

1. Turn signals only work when completely stopped, or if my headlights are off. If I'm driving with my headlights on, they don't work. But will work when my headlights are on and to 100% complete stop.

2. My head unit works perfect when stopped.....but when driving and I let off the gas, the stereo shuts off lol. Every time I give the truck gas and let off real fast only the indash shuts off.


Any help on these issues would be greatly appreciated.
Click to expand...
 
Once again the ignition switch and the wiring and connector. Also check the battery post connections, need to be clean enough to eat off of, LOL

Hardrock2401 said:
Can't figure out how to edit. But I meant when the headlights are off and driving, they work.
Click to expand...
 
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