85 720 turn signals blink backwards on dash fuel guage stays at full water guage goes to hot quicker than should,everything works properly on outside of vehicle

[Cecil wilmer]

85 720 turn signals blink backwards on dash,fuel guage stays full,temp guage registers hot,I cleaned hazard switch with contact cleaner everything worked well for ,2 days,everything working properly on outside

[DwayneOxford]

Try cleaning and lubing the 4 way switch.

[datzenmike]

I'm still trying to come to grips with the signals blinking backwards.

 

Put the wire off the temperature sender on or near the thermostat cover on the intake. Does the gauge still read?

[DwayneOxford]

Sorry, missed hazard switch. Did you unplug it's harness connector? May've lost a ground somewhere? Remember Mike posting on the voltage regulator that temp and gas gauges share on 720 World.

 

[Logical1]

4 hours ago, datzenmike said:

I'm still trying to come to grips with the signals blinking backwards.

Honestly that would take work and INTENT to make happen!

 

The hazard switch on these trucks is the weakest link in many many ways. I have worked on dozens of 720s and every one is temperamental. I just brought one back to life today with copious amounts of QD contact cleaner and vigorous switching off and on. I noticed also that they are different from the 2wd to the 4x4 or maybe just the 84' to the 85' but the 85 4x4 has many more wires and a different harness plug.

[datzenmike]

I spent upwards of an hour trying to find out why the emergency 4 way flashers work but when turned off, the signals did not. What happens is when the switch turns the 4 ways on it disconnects the turn signals. When you move the 4 way switch to off it travels past the connection for the signals and they just remain disconnected. What you do is turn a turn signal on and slowly push the 4 way switch towards on.  At some point the contacts will make and the signal will begin flashing. Stop there. Now all you have to do is remember this next time you use your 4 ways and the signals mysteriously stop working. 720s are weird this way.

[Logical1]

As much as I appreciate a band-aid that I can attest to working, A true fix would be best. I will spend some time, researching a better switch option! Everyone should have functional hazards as well as blinkers... Besides BMW & Merc drivers whom have their turn signal lever cut off at the factory!

[datzenmike]

It's in the 720 4 way switch design. If one does it there's a good chance it will happen on a lot of them.

[Cecil wilmer]

Turn signals blink backwards on dash,fuel guage goes to full,everything works as it should on outside of vehicle....help?

[WestPac720]

I don’t understand what you mean by the turn signals blink backwards? Could you expound more..

[WestPac720]

As for the fuel gauge reading at max, you could be grounding somewhere or have a short. Also have you checked the fuel sensor in the tank?

[DwayneOxford]

Maybe figger a way to put a stopper on the switch?

[datzenmike]

Or just simply adjust it after using.

[datzenmike]

Temperature and fuel gauges...

Are powered by a voltage regulator that supplies an 8 v supply. This way the gauges do not read higher or lower when the alternator charges between 12 and 14.4v. Both gauges run on this 8v supply and the other end runs through a variable resistance to ground through the temperature sensor in the intake and the float in the gas tank. The lower the resistance the higher the gauge reading. So if you disconnect the temperature sender the gauge should read cold.

 

The fact that both gauges read high would seem to indicate that the voltage regulator is involved. 

[datzenmike]

Two posts on the same subject???? I merged them together.

[Cecil wilmer]

If I turn on turn signal to show left turn it's correct on outside of vehicle but it shows on the dash as turning right.and vice versa.i cleaned hazard switch with contact cleaner,I replaced hazard switch,bought 2 from junkyard still doing same thing.im gonna check out voltage regulator.i have a new alternator just put on,also put new plug on alternator.

 

[Cecil wilmer]

Sorry guys I'm new to this,I really do appreciate all the help,

 

 

 

 

 

[datzenmike]

It's OK reversed signals now make sense.

 

Well the lever movement and the flashing turn signals are correct so someone has had the dash out and somehow reversed the wires to the indicator lamps in the dash