Well I hope everyone had a nice Christmas and New Year celebration, and stayed out of jail:D
It's been cold in my shop and I've been sick, so I haven't gotten anything done on the 88 till today.
The headlight/fog light flashing issue has been resolved with a change of headlight switch. I left the lights on for over 40 minutes with no flashing present (took much less time for them to go nutz before)
So I moved on to pulling the dash apart with intentions of 1)fixing the dash lights lighting the right side of the IP and 2) doing something about the ground for the gauges.
Well....best laid plans and all that. The two bulbs on the right side of the cluster both check good. I also checked the ceramic resistor located next to them just cause it was there. It buzzed out to (if I remember correctly) about .25 ohm. No problem with it I'm sure, since a problem with it would affect all the dash lights. So I'm at a bit of a loss as to why these two lights aren't lighting up.
On to the gauge issue. If I remember correctly, someone told me the ground would be an ORANGE wire in (I believe) the #15 spot on the 18 pin connector. Well there is a green wire on pin 15. But what's really cool is there is a BLACK wire on pin 7 that is not connected to anything. (pic below)
So can anyone advise here? Is pin 7 the ground? If not, which pin is? (buttstuffog gauges in the TC btw)
Also, behind the headlight and fog light switches there are a couple of things dangling. As you might be able to tell in the pic below one is just a black box (with wires) that looks like it might have a bracket on the bottom. The second (much larger) black box has a bracket that you can easily see in the pic. Problem is I can't tell where these are supposed to be mounted. I'm assuming they're supposed to be mounted to something, but what? Any ideas?
Lastly if you all remember I had posted saying I had found replacement headlights for about $42 ea. I ordered some and said I would post a pic when they arrived. Well they're here, are real FORD issue, and look super.
Black wire in position 12 of the 18 pin connector is the ground for the IP illumination.
The black wire that goes nowhere in position 7 is correct.
Thanks much. Any idea which wire is ground for the gauges themselves, or is it the same ground?
The grounds for the gauges is through their individual senders.
Fuel gauge sender, oil pressure gauge sender and temperature gauge sender.
Voltage for the IP illumination is on position 13 of the 18 pin connector. It's a LB/R wire.
How much voltage depends on where the dimmer part of the headlight switch is set. The headlight switch must be in the park or headlight position.
Voltage on the LB/R wire also lights a bunch of other bulbs.
Ash tray, shift indicator, radio, clock, cigarette lighter, etc.
Ok...I'll buy that. Maybe. Assuming these are done like on a MOPAR IP, the gauges have ONE COMMON trace, which is B+ (power) then the second runs to the sender which floats ground.
IF THAT IS TRUE, then the original discussions on this subject where someone suggested a "bad ground" for the gauges CAN'T be the problem. It would have to be (as I originally suspected) a problem with the B+ (power) to the gauges that is making them read high when the lights are turned on.
Anyone concur? So IF that is the likely source I need another IVR. One was supposed to be coming in the mail, but it never arrived.
I'd like thoughts on that, on these two black boxes floating around behind the light switches, and why with good bulbs I have no lights on the passenger's side gauges. Bad trace maybe?
Thanks all
Installed the new headlights today. I see what people were referring to about not breaking the adjusters. After giving it some thought, I broke out the old Weller soldering iron and melted the small wedges off the headlight. Then I took my knife and made sure the surface was as flat as I could get.
Despite my best efforts a couple of the adjuster bases lost a piece anyway. BUT my efforts were rewarded, cause all of the adjusters kept at least one "lock". So I got them all off and back on the new headlights and managed to leave them adjusted the way they were.
I chased down every pin on the 18 pin connector. Pin 12 is the only ground. So it must be the ground for the IVR as well as the bulbs.
Can you get at the cluster to troubleshoot with the cables connected?
C285 is the 18 pin connector in the EVTM diagram. Pin 10 will have the 5v output from the IVR. See if it changes with headlights on.
I think I read somewhere that the IVR 5v is a pulsing voltage. You may have to look at it with the meter on AC.
The input voltage for the IVR is pin 7.
(http://mysite.verizon.net/vzetk5cc/sitebuildercontent/sitebuilderpictures/Gauges23.jpg)
Thanks much. The diagram will be a big help. My guess about the pulse voltage is you are probably correct. This IVR looks really similar to what MOPARS used, and they made the proper voltage by making and breaking a set of contact points inside the canister (think distributor points) So basically they break open when the 5V is reached, then close again building back up to the 5V. Also on the MOPARS it wasn't uncommon to look down and see your gauges momentarily pegged from the points in the IVR sticking and allowing a full 12V to the gauges. (most people don't know the cause of their gauges pegging)
Anyway, there isn't enough slack in the main harness to get behind the cluster with it plugged in. But IF the voltage to the gauges is going up when the lights are on a while, I'm still making a S.W.A.G. that it's the IVR that is causing it. HOPEFULLY having replaced the headlight switch will have an affect on all this as well. There was an obvious problem with it which has now been eliminated.
Thanks again. I'll make sure and let everyone know what the cause of this is when I figure it out.
Since I ran down all the pins on the 18 pin connector (C285) I may as well post them here. You may find something useful.
1. R/Y Hot in start or run. Fuse 18
2. W/PK Overboost warning indicator.
3. P/W Brake indicator.
4. Y/W Fuel Gauge sender.
5. R/O Ammeter.
6. Y/LG Ammeter.
7. GY/Y or BK/LG and a BK to nowhere. Hot in run thru a 8.5 ohm resister wire. Input voltage for the IVR.
8. W/R Oil pressure gauge sender.
9. R/W Temp gauge sender.
10. DG/W IVR 5v output to low fuel warning module (optional indicators)
11. DG/LG Fasten seatbelts indicator.
12. BK Ground.
13. LB/R [COLOR="Red"]Illumination voltage from headlight switch dimmer[/COLOR].
14. W/LB Right turn indicator.
15. LG/W Left turn indicator.
16. DG/Y Tachometer
17. LG/BK [COLOR="Red"]High Beam indicator[/COLOR].
18. DG/W Speed sensor.
Thanks much for posting that. It is a help in a way, cause it leads me more to believe there may be a problem with the IVR. Besides the circuit "floppy" it's the only thing common to all the gauges. I had sent my home address to someone back on 11-19 for them to send me an IVR, but it was never sent. No one around here has a new one in stock, and I'm tired of this thing sitting in the shop in pieces.
SO I'll be putting it back together with the original IVR and hope that changing the headlight switch has somehow fixed that problem as well as having fixed the flashing headlight issue. I can't see how it would fix the gauge issue, but I can't see how it was affecting them to begin with. But it did, so we'll see.
Thanks again
you know,,
its high time all of us get together and find out whats inside the IVR.
Vinnie will hopefully remember to try and snag one so we can have some fun. this part needs reverse engineered so we can repair or duplicate them with of the shelf parts.
I'm betting it's like the MOPAR piece and has contact points in it. There is an electronic replacement for the MOPAR IVR, so you would think there would be for one of these as well.
I can tell you they're expensive. Costs more than what I just paid for a replacement headlight
as a test,
what would be wrong with substituting the ign sw A1 connection to cluster pin 7 connection with a decent wattage potentiometer preceeded by a fuse? Dial in 5 to 5.2vdc on the center tap output and let that be the power source for the guages.
the schematic illustrates some sort of thermal contactor type three leg device anyway with a center tap output to source power to all the guages. To be honest, the ivr symbol reminds me of something that would reset itself if it got too hot.
Problem is for me to do a teat under conditions where the problem manifests itself I need to have the car running at operating temp and have the lights on for a period of time. Pretty much would necessitate the IP be in it's normal position, and two of the connections on the IVR are basically snaps.....like on a western shirt or a 9v battery
If you have the optional indicators, low fuel and low oil, you may want to unplug the low fuel warning module. The 5v IVR voltage goes to this module. DG/W wire #367.
The EVTM says it's "Mounted behind upper RH side of I/P".
(http://mysite.verizon.net/vzetk5cc/sitebuildercontent/sitebuilderpictures/LowFuelModule.jpg)
I'm sure it has those, since I just replaced the low oil sender (cause it was leaking) Question is why would I want to unplug that, other than dropping the load on the IVR?
In case the module has a gremlin that is screwing with the IVR voltage.
Scott, I think this article might answer your questions about the IVR:
http://www.turbotbird.com/techinfo/ivr/improved_design_solid_state_IVR.htm
It would cost more, but a DC-DC converter would be more efficient might eliminate the need for the heat sink.
If my math is right, a linear voltage regulator is ~35% efficient going from 14V to 5V. A DC-DC Converter would run between 75-90+% efficient.
So the OE IVR is a mechanical like the MOPAR ones. Makes sense.
I put the car back together today and took it out for a 40 minute drive. I started by letting the motor get to operating temp on a 12 mile jaunt. The temp seemed to be just hunkie dorie. So then I turned the lights on (just the headlights) and continued driving. Eventually the temp red towards the high end of the normal range, but never read as hot as before (basically pegged) and you could see the gauge move up and down with the cycling of the fan and/or thermostat.
At one point, however, the light to show the suspension in "FIRM" went out, and stayed out until I turned the headlights off. Not sure why THAT happened, but it did.
So the bottom line is:
It seems the headlight switch replacement fixed the flashing problem
It also seems it helped (somewhat) with the gauges reading high problem
I still believe the IVR should be replaced (with a digital unit)
I've found TWO places that sell an electronic IVR. One is made to be a direct replacement for the MOPAR O.E. unit (which doesn't have the 9v battery snaps) the other unit is one that could be used on Fords quite easily.
Here are the links:
http://rt-eng.com/mediawiki/index.php/RTE_ABlimiter (O.E. unit)
http://www.demonivr.com/Superior.html