Retrofitting trailer wiring on a 1997 Safari

[Bret Schmerker]

For a 1997 GMC M11006, I've plans to fit a six-circuit isolator for the trailer wiring, so that any problems in the trailer not take out the van's lights in the process. I've ID'd all but two wires on the jack compartment stub harness (viz., 9 - 0.8 BR Tail Mrkr Lic; 18 - 1.0 YL, Left BT; 19 - 1.0 DGN, Right BT; 24 - 1.0 LGN, Back Up; 1642 - 2.0 OR, +Vcc UPFIT BAT; 1647 - 2.0 DBL, TRLR BRK DRIVE); only the 1.0 WH and 2.0 WH are yet to be identified in terms of the official General Motors circuit number table. Two connectors from Pollak are under consideration for the trailer receptacle: The 9-pin Fifth Wheel Utility Socket (P/N PK 12-907), and the 7-pin RV/Utility Socket (P/N PK 12-707E). ...

In addition to ID's on the two white wires described above, would anyone have information on solid-state relays (not more than 35 A @ 12 VDC) suitable for the isolator and the sockets they would require? (My trailer set-up involves what is essentially a backport of the rear-body fuse and relay panel from the Chevrolet/GM City Express; the backport has ATM fuses for all trailer load feeds in the design.)

[Astrophysics]

Hi,

You may want to consider regular 20 A / 30 Amp relays. And also, your local RV trailer supply can order a 50 amp solenoid switch . No need for solid state relays.
Make sure to put fuses or resettable circuit breaker in charging lines. Also, put LED bulbs in trailer tail lights for low current draw.

AP

[Bret Schmerker]

Update: Information from etrailer.com has 20 - 1.0 WH - Ctr HM Stop Light and 1650 - 2.0 WH - Trailer Ground Return. That means another circuit retrofit, this time from the engine compartment to the jack compartment: I see need for a distinct circuit-breakered "Hot At All Times" power supply for the rear circuit panel backport to separate the +Vcc Trlr Lights (which I'm preliminarily identifying as Circuit 1602 - 2.0 RD) from the existing +Vcc Upfit Batt (Circuit 1642 - 2.0 OR). Solid-state relays still preferred, but I'm investigating a full suite of LASFIT® LED relamps for the exterior to get power consumption under control; the tricky part will be a flasher that can run 75 cycles/minute with a 1A load.

[Bret Schmerker]

Update 2: Hella AG manufactures a satisfactory solid-state relay in Mini ISO Relay H41773001 (Part Number 9 317 739 87), an SPST-NO design rated for 20maxA@12VDC. Whether six or eight needed depends on the trailer socket, but Painless Performance manufactures the best candidate for the trailer fuse block retrofit found as of 15 October 2019 in Model 70117, which hold up to eight ATO fuses. Now, if I can figure out how to splice and locate that 100A breaker for Circuit 1602....

[Bret Schmerker]

Update 3: One thing I'll need for a watertight, flood-proof connection for harnesses such as the Pollak® PK 11-998 or equivalent? A properly-specificated CANNON® connector set through the bottom of the jack compartment. With two pins needing 100maxA current capacity, two pins 50maxA, and the remaining five pins 25maxA, who among the Forum membership with line-voltage electricals experience would have a recommendation for specific part numbers of watertight plug and bulkhead socket? (The CANNON connectors use a large screw-thread collar for locking.)