Joined: Nov 19, 2010 Posts: 107 Location: ITALY - TUSCANY
Posted: Tue Jun 12, 2012 11:25 am Post subject: SPIDER HARNESS ON M38A1 TO TEMP GAUGE "INSIDE" CON
I have the feeling that this question is so dumb and the answer so obvious that I am reluctant to put it on the forum. But what the heck. Here goes! In putting my 1953 MD58270 back together, I find that my spider harness has 4 "female" Douglas connectors. Thus the spider harness will only connect to the right hand connector (looking at the back of the gauge). I have checked 3 temperature gauges and all three have the male Douglas connector on the "outside" i.e. on the right when looking at the back. This seems to be standard procedure inasmuch as the fuel and pressure gauges all have the male on the right when looking at the back. But when I go to TM9-804A at Fig. 89 (page 193) I see the spider harness wire going into the left hand connector on the rear of the temperature gauge and the right hand connector on the pressure and fuel gauges. Then I checked a thread on this site. On May 16, 2006 Cacti_Ken posted a "Question on Wiring Diagram". GregS responded on 17 May saying "Power to those gauges is supplied by the instrument harness which is wire "27". The "inside" terminal of the fuel, oil and temp gauges are connected to the wiring harness. The "outside" terminal on those gauges connect to the sending units." I presume that position is referred to as "inside" because that connection is closer to the center of the instrument cluster than the other connection of the gauge. The manuals all agree that the wire connecting the temp gauge to its sending unit should be number "33". I don't have that wire made up yet, so I can't check to see if it ends in a male or female Douglas connector. If the spider should go to the inside of the temp gauge, then one of the Douglas connectors would have to be male. I wonder, did someone switch the Douglas connector on one of the wires of my spider harness from male to female or are the TM and GregS wrong and if so, why has no one corrected them? I am stuck and would appreciate your help. Thanks again David aka bluewatersailor. _________________ David Manning
1952 M38A1, 1953 M38A1, 1954 M38-A1, 1952 M100
Photos on Page 10 of Members Albums.
All of the illustrations in TM's 9-804 (M38), 9-8012 (M38), 9-804A (M38A1), and 9-8014 (M38A1/M170) show the inboard terminal as +24V on all three powered gages except the early M38 cluster with the 90 ohm resistors connected in line with the gage and the M170 cluster which is a hermaphrodited Packard combined with Douglas connector spider.
These illustrations are from TM 9-804 & TM 9-8012 for the M38. The early illustration shows the 90 ohm resistors and shows the water temp gauge +24V on the outboard. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Nov 19, 2010 Posts: 107 Location: ITALY - TUSCANY
Posted: Wed Jun 13, 2012 1:00 am Post subject: SPIDER HARNESS TO TEMP GAUGE
I, too am looking at the right-hand picture. I am unable to accomplish the connection shown, so I must conclude that 1 of the 4 connectors on the spider harness has to be different from the other 3, i.e. - it has to be male in order to connect to the inside terminal of the temperature gauge. Confirm? _________________ David Manning
1952 M38A1, 1953 M38A1, 1954 M38-A1, 1952 M100
Photos on Page 10 of Members Albums.
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum