I have replaced the water pump (DD6V92) fan switch, had all the fluid flushed and the engine seemed to run hotter than it should 197-205 sometimes 210. Since the dash air doesn't work I always had just the AC fan on and the overhead fan on. Well come to find out when these fans are on they add 10-15 degrees to the temp gauge. Does anyone know why this is happening?
Thanks,
Woodie
Modified topic title to be more descriptive - Michelle
I would guess a voltage issue. My '81 would change the speedometer when I turned on the headlights.
This exact temp change happens on my 1991 6V92 temp gauge. Headlights affect it some, but the dash fan raises it 10 degrees or more as you have noted. This is due to a voltage drop in the dash wiring. I have learned to make the correction in my head when I read the temp.
I remember in the 60's we had voltage stabilizers on the back of some gauges especially fuel on the old Fords I had.
Hans
Just a note on gauges. I have been reading a lot about VDO ones as my water temp one is either gone or sender gone. The one thing I noticed mentioned with strong wording is that they should all have a good minimum 14ga ground wire to a single good frame connection. FT has not done this so will someday (after I figure out my gauge) do this for all of them.
It sounds like it does make a difference on the reading.
JohnH
I have also noticed that the dash a/c fan will make my 95 u-240 3116 water temp raise by 5-10 deg. Bad ground could be the problem, but I have not found the reason.
Pat
On my to-do-list is to run a new 4/0 ground cable from the battery bay ground to the dash ground post. I think the OEM braided ground wire used by Foretravel is inadequate. This will be better than using the frame for ground, on a 25 year old coach.
...also when driving in the pouring rain the temperature gauge will suddenly go all the way to the top of the scale, because the rain water has grounded out the temperature sensor ...so clean up the sensor and seal it with Liquid Tape ...and your gauges will go wonky if your ignition solenoid is about to fail
Not sure when Foretravel changed but the 80's and it seems some early 90's coaches had the frame as the ground path primarily.
My 97 has a large collection of green wires to a wire mesh grounding bar under the dash.
My guru buddy removed the wires from my dash gauges and crimped the contact tabs tighter then reinstalled them.
Volt gauge flucuations went away.
This got me thinking. My ignition solenoid is original and 25 years old as far as I know.
I went over to the coach today with a voltmeter and took some readings across the ignition solenoid main contacts with the ignition switch turned to the "on" position (one click) - and then switched the heater fan on and off - this is what changes my temp gauge reading by 10-15 degrees:
- Heater fan off - 0.15 volt drop across solenoid
- Heater fan full on - 0.5 volt drop across solenoid
Not Good!!I have ordered this solenoid on Amazon with silver tungsten carbide contacts, will be replacing the solenoid before the next trip. I'll measure and post voltage drops with the new solenoid for comparison.
Cole Hersee 200 amp continuous duty solenoid (https://www.amazon.com/Cole-Hersee-24213-Continuous-Solenoid/dp/B005K2429I/ref=sr_1_1?ie=UTF8&qid=1466190846&sr=8-1&keywords=cole+hersee+solenoid)
"I remember in the 60's we had voltage stabilizers on the back of some gauges especially fuel on the old...,
Impressive, you were there AND you can remember it in detail? 😜 ✌
My ignition solenoid was the electrical problem on my coach several years ago. At one point it only allowed about 7 or 8 volts across causing the electronic engine computer to shut down. The contact surfaces were carbonized, replacing this solenoid that is under the dash behind the speedometer makes a big difference in all 12 volt electrical accessories. ^.^d
If you ever find yourself stranded due to a bad ignition solenoid you can swap it with the boost solenoid behind the panel over the battery box. On my coach they're the exact same solenoid. Also notice that the little black box Bosch relays are all the same and there's at least one spare under the dashboard that you can use for a field repair if it leaves you stranded.
I did have some off days during those times....and its coming back now 8) 8)
Peter, I am really surprised that with all your knowledge and expertise electrically that you have not taken that ign' solenoid apart like I have done and clean it up. That is all that is needed but I do understand that $37 is a small price to pay for a good new one. Once you do install the new one then take it apart to see and file contacts faces and "washer"
JohnH
John, yes, I did repair my boost solenoid as you have described and it has worked well for 4 years. I wanted the new silver tungsten contacts for minimum resistance, to see if that solves my engine temp gauge reading high. I do plan to repair this one and keep as a spare.
You probably already know this, but don't use an emery board or any other type of sandpaper to clean electrical contacts because the sand will melt into glass, which is an insulator. This is true on high voltage AC contacts also. It's best to use one of those little ignition point files if you can find one... Unfortunately I can't find mine at the moment because it's so small it disappeared on me! haha
Metal fingernail file can be used in an emergency.
It dates me, but a match book striker works well.